Inauguration day is all about pomp, pageantry - and pictures.

The clothes worn on this world stage - the colour, cut and details - take the spotlight. From Melania's striking hat to Usha's fashion forward overcoat, here's a quick roundup of some of the day's most memorable looks.

Melania Trump kicked off inauguration day with an outfit that has all the hallmarks of her favoured first lady style: sharply cut, with spiked heels and a dramatic flourish via the headgear. It is simultaneously serious and chic.

It also speaks to her love of hats, which has sometimes got her in trouble – for example her widely criticised colonial-style pith helmet on safari in Kenya.

Hats have long been a staple of First Lady inauguration dressing, from Jackie Kennedy's pillbox hat to the hats worn by Nancy Reagan to each of her husband's inaugurations, the first one "Reagan red" and the second one blue.

But while some hats feel like an addendum to an outfit, others take on more main character energy – as does Melania Trump's today.

The brim is wide enough and the contrast between the cream ribbon and navy hat big enough that it draws the eyes upwards – even if it obscures the eyes of the wearer, a person who is famously hard to read.

What designer the first lady wears to the inauguration is the subject of fascination – and an opportunity to transmit a message. That Melania chose New York Designer Adam Lippes and a coordinating hat by Eric Javits, was a marked shift of gear.

She may have worn the American fashion designer Ralph Lauren to her husband's last inauguration, but much more frequently turns to the big European houses. Unlike Lauren, neither Lippes nor Javits are such household, starry names. Fittingly, Lippes recently opened a new boutique in Palm Beach, where the Trump's have Mar-a-Lago, or their "southern White House".

Very much on-brand is the price tag: Melania is known for her extravagant tastes – many of her outfits while previously First Lady had price tags running well into the thousands – and Lippes' dresses, for example, go from $1,200 (£1,000) up to over $9,000 (£7,500).

As with much of Melania's aesthetic, her look today will most likely be the work of a collaboration with her stylist Hervé Pierre, a French fashion and costume designer who has worked at Balmain, Oscar de la Renta and Vera Wang and is a former creative director at Carolina Herrera.

His extensive experience working in the theatre will mean he understands well the idea of how to make an outfit sing on a stage – although no theatre will be quite as exposed, watched or critiqued as the world stage playing out today.

Former first lady Jill Biden yet again wore a purplish blue from head to toe.

Blue is a very on-brand colour for the entire Biden family and it has come to represent the administration of the last four years.

At her husband's swearing-in ceremony in 2021, Jill wore a blue coat created by designer/founder Alexandra O'Neill for the New York–based luxury womenswear label Markarian. It reportedly quintupled sales for the designer. It was custom made and embroidered with Swarovski crystals, plus had a pandemic-era matching face mask.

Both Bidens have chosen today to dress in clothes by the all-American designer Ralph Lauren, whose clothes and back story are often seen as synonymous with the American dream.

It comes as no surprise: Jill has worn his clothes throughout the last four years and was at his fashion show in the Hamptons last September.

Her husband recently awarded Lauren the Presidential Medal of Freedom - the nation's highest civilian honour - and in the process made him the first fashion designer to receive the distinction.

Ralph Lauren suits have been a fitting uniform of choice for the outgoing president. On the White House website as he leaves office, it sums up his presidency: "for all Americans, a country for all Americans, a future for all Americans."

You could argue his Ralph Lauren suits are also designed to not leave any Americans out – never straying too far from classic blue and classic lines.

First daughter Ivanka Trump matched Melania's serious colour palette with an emerald green skirt suit with a matching hat.

The hourglass silhouette – the cinched in waist and fuller skirt – felt pointed and intentional. It was reminiscent of Dior's glamorous New Look, which ushered in a new era in fashion after World War Two.

The asymmetry of the cut, however, sounded a note of continuation: Ivanka wore a white Oscar de la Renta jacket with an asymmetric handkerchief hem for inauguration day in 2017.

The first daughter's outfit feels like it could be harking back to the work of Adolfo Sardiña, a Cuban-born American fashion designer who started out as an apprentice milliner at Bergdorf Goodman in the late 1940s and went on to be known for his spectacular hats, which were worn by Nancy Reagan to both of her husband's inaugurations.

The lawyer and wife of Vice President-elect JD Vance, Usha Vance's most high profile appearance to date was speaking the 2024 Republican National Convention. For the occasion she chose a cobalt blue off-the-shoulder Badgley Mischka dress, which retails for $495 (£400). According to a spokesperson speaking to industry website WWD, Vance must have bought the garment herself as the brand wasn't consulted.

But there were clear signs of a pivot to more high-fashion choices this weekend in Washington, when the incoming Second Lady wore a custom black velvet gown by Oscar de la Renta for the Vice President's Dinner and a smart white double-breasted coat to the wreath-laying ceremony in Arlington cemetery earlier in the day.

Today, she chose an overcoat with a strikingly fashion-forward detail: a scarf intentionally tucked into her waist-height belt. Is it a sign of a more stylised image to come as Vance takes her place as the second lady?

Suits, ties, shoulder pads, pearls; these are the traditional attire of inauguration day. But John Fetterman, the US senator from Pennsylvania since 2023, has never been one to stick to traditional dress codes – he wore a Carhartt hoodie with a picture of a bow-tie printed onto it for the White House Correspondents' Dinner last year.

Still, if tradition didn't mean Fetterman opted for a pair of trousers, you would have thought the weather might – temperatures in Washington today are so low that the ceremony has been moved inside for the first time since 1985. Yet Fetterman showed up coatless, in only a hoodie, and wearing shorts.

It is fitting – Fetterman is all about bucking convention – he was, after all, the first Senate Democrat to meet with Trump since the election.

At Bill Clinton's 1997 inauguration, Hillary Clinton wore a candy floss-pink outfit by Oscar de la Renta. And to her husband's first swearing-in ceremony in 1993 she went for an unusually busy look for a first lady on inauguration day, when block colours tend to be the order of the day: a checked suit by Arkansas designer Connie Fails and a blue velour hat by Darcy Creech.

In 2017 at Trump's first inauguration, she wore a white and cream Ralph Lauren pantsuit - the outfit that clearly makes her feel most battle-ready and professional.

Today, in marked contrast to her previous palette, she has gone for a grave navy. On her coat there is a single brooch.

Its details remain unclear but brooches are often the site of sartorial messaging and Clinton knows it. She recently wore a bald eagle brooch – a national symbol – with the US flag on it for the funeral of Jimmy Carter.

The look was by British sustainable designer Stella McCartney, a move that feels like it could be aimed at the incoming administration's climate plans.

Trump has confirmed plans to once again pull the US out of the Paris agreement, which tries to mitigate the worst impacts of the climate crisis.

Elon Musk, a close adviser to Trump, CEO of Tesla and owner of X has, along with a bevy of fellow tech entrepreneurs that some have dubbed "the broligarchs", been turning heads with their fashion choices of late.

Most recently in Musk's case, a Belstaff jacket drew the internet's eyes, while Mark Zuckerberg's style makeover has seen him transform from "normcore" grey T-shirts and inconspicuous jeans to luxury labels, his own brand of slogan T-shirts with Greek and Latin phrases and million pound watches.

Today, Musk is wearing a suit that looks unremarkable except for one detail: a slightly wonky tie.

In a move that could easily be out of former UK prime minister Boris Johnson's sartorial playbook, Musk has gone for a hint of dishevelment on a serious and ceremonial day.

In the final minutes of his presidency, Joe Biden pre-emptively pardoned several family members, including his brothers James and Frank Biden, and sister Valerie Biden Owens.

Biden said the pardons were intended to shield his family from politically motivated attacks and should not be mistaken as an acknowledgment of any wrongdoing.

The eleventh-hour move follows another set of pardons issued to Covid response chief Anthony Fauci and members of the House 6 January riot investigation to prevent what he called "unjustified... politically motivated prosecutions".

The outgoing president said: "Our nation owes these public servants a debt of gratitude for their tireless commitment."

Donald Trump regularly clashed with Dr Fauci during the pandemic and has suggested he would take action against those who tried to hold him accountable for the 6 January Capitol riot and other "enemies from within".

For years, Trump has levelled unproven accusations of corruption at both Biden and his family. In 2023, House Republicans launched a nearly yearlong investigation into the Bidens, examining their business dealings abroad, but found no criminal wrongdoing.

"My family has been subjected to unrelenting attacks and threats, motivated solely by a desire to hurt me," Biden said in a statement released as Trump arrived at the Capitol rotunda for his inauguration.

"Unfortunately, I have no reason to believe these attacks will end."

In addition to his siblings, Biden issued pardons for his sister-in-law Sara Jones Biden and his brother-in-law John Owens.

The outgoing president had previously issued a pardon for his son, Hunter Biden, who was facing sentencing for two criminal cases.

As he prepared to leave the White House, Biden also commuted the life sentence of indigenous activist Leonard Peltier, who was serving a life sentence for the 1975 murder of two FBI agents. Peltier will transition to house arrest, Biden said in a statement.

On Monday morning, a Trump spokesperson has called Biden's pre-emptive pardons "the greatest attack on America's justice system in history".

"With the stroke of a pen, he (Biden) unilaterally shielded a group of political cronies from the scales of justice," Taylor Budowich, Trump's incoming deputy chief of staff for communications and personnel said in a post on X.

"This is yet another dangerous and unreversible erosion of American norms."

Biden also issued a pre-emptive pardon to Mark Milley, a former chairman of the Joint Chiefs of Staff, who last year described Trump as "fascist to the core".

Biden's statement said that the pardons should "not be mistaken as an acknowledgment" that any of those covered "engaged in any wrongdoing".

Democrats had warned the outgoing president against such action. Adam Schiff, a Senator for California, said Biden could set a "precedent" for "each president hereafter on their way out the door giving out a broad category of pardons".

Dr Fauci told US media that he "truly appreciated" Biden for taking action, adding that the possibility of prosecution had created "immeasurable and intolerable distress" on his family.

"Let me be perfectly clear, I have committed no crime and there are no possible grounds for any allegation or threat of criminal investigation or prosecution of me," he added.

Gen Milley, 66, thanked Biden in a statement and stated that he did not wish to spend the rest of his life "fighting those who unjustly might seek retribution for perceived slights".

"I do not want to put my family, my friends, and those with whom I served through the resulting distraction, expense, and anxiety," he said.

Biden's pardons cover all members of the House Select Committee that investigated the 6 January riot, as well as their staff and the officers who testified.

The committee was led by Democrat Bennie Thompson of Mississippi and former Republican Congresswoman Liz Cheney of Wyoming, who later campaigned with Trump's opponent, Vice-President Kamala Harris.

Trump in December backed a call for the FBI to investigate Cheney over her role in leading Congress's probe.

But the pardons do not shield the officials from congressional investigations. The recipients could be subject to probes from a Republican-led Congress that require them to testify and provide other materials.

Former US Capitol Police officer Harry Dunn said he was "eternally grateful" to Biden "not just for this pre-emptive pardon, but for his leadership and service to this nation".

"Unfortunately, the political climate we are in now has made the need for [a pardon] somewhat of a reality," he said.

"I, like all other public servants, was just doing my job and upholding my oath."

Trump is set to pardon some of those convicted of crimes related to the riot.

"You're going to see something tomorrow," Trump said on Sunday, in reference to the 6 January rioters. "I think you'll be very, very happy."

On the campaign trail, Trump railed against "enemies from within", and has endorsed several figures who have vowed retribution against his foes to join his cabinet.

However, his choice for attorney general, Pam Bondi, said during her confirmation hearing last week that there would never be an enemies list and that she would not use the justice department to target anyone based on their politics.

Donald Trump loves a show and he likes to surprise people.

And as he returns to the White House, the world is waiting to see if Trump 2.0 will really be a more disciplined and effective version of its previous, chaotic, incarnation.

But even before he steps back into the Oval Office, the single biggest difference between now and the start of his first term eight years ago is just how bold he feels.

Talking to people around Trump, the confidence is unmissable. He has the GOP in lockstep, the business community falling over themselves to donate money to his inauguration and an opposition that is exhausted and largely quiet.

The election was actually quite close, but you wouldn't know it from Maga world. They feel vindicated and want to move fast to get things done, to hit back against the incoming president's enemies and to change America. They believe the country backs Trump's disdain of "woke" agendas, mainstream media and global elites.

And the agenda reflects this. From the mass deportation of migrants and pardons for Capitol rioters, to punitive trade tariffs on America's neighbours and an end to birthright citizenship, there's a lot of fundamental change being promised and he could announce much of it on day one.

The effect would be dizzying - and that is the point.

The team that Trump will be bringing into the White House reflects that brashness. Gone is the president who seemed in awe of hierarchies and establishment credentials.

Take his picks for secretary of defence.

In 2016 Donald Trump chose Jim Mattis to lead the Pentagon, almost fawning over the longtime general "who everyone loves".

He hailed Mattis as "a man of character and integrity." (Two years later Mattis would quit amid very public differences of opinion and Trump would call him "the world's most overrated general." )

Fast forward to 2024 and Trump has picked a very different defence secretary: Pete Hegseth is a TV host with a military background but no significant management experience, who seems to have survived his Senate confirmation hearings despite multiple accusations of sexual abuse and drunkenness.

Trump isn't out to impress anyone this time, and the Republican Party seems to have no ability or interest in providing checks and balances on his instincts. Trump standing by Hegseth as scandal swirled was seemingly a test for Republican lawmakers. Would they dare to defy Trump? They didn't.

So, for the moment there is unity - but look below the surface and there's less harmony, and with it the prospect of more chaos.

Trump's cabinet is a team of people with surprisingly different views who may not always play well together.

His pick to run health care, Robert F. Kennedy Jr, is a pro-choice former Democrat at a time when many Republican lawmakers want to restrict abortion access.

The nominee for Treasury Secretary, Scott Bessent, embodies old school Republican economic values and comes from Wall Street via a stint working for the liberal financier George Soros. But Trump's Vice-President - JD Vance - is a populist who says "we are done catering to Wall St." There is Elon Musk with his deregulation agenda serving alongside a Labor Secretary nominee who is pro-union and pro-worker safety regulations.

Trump's pick for Secretary of State, Marco Rubio is in the conventional, hawkish Republican mode. He has called Vladimir Putin a "thug" and a "gangster." Meanwhile Trump's pick for director of national intelligence, Tulsi Gabbard, who has been sympathetic to America's adversaries, including Russia and Syria's now-deposed leader Bashar al-Assad and was described to me by a Trump ally as a peace-nik, "the Jimmy Carter" of the group.

Allies of the incoming president argue this unconventional mix of views is what makes Trump different, and exciting. A former Trump adviser told me that the uniformity of opinions in previous Democratic administrations was like "a bunch of parrots." The whole point of Trump's second term, this adviser said, is to shake up a stultified system of government.

Historian Doris Kearns Goodwin famously credited Abraham Lincoln for creating a cabinet that consisted of a team of his rivals. In Trump's case, this incoming administration feels more like a court than a Republic. The courtiers have their divergent views and disagreements with each other and they have to get as close as possible to the man in the center of it all for their agenda to win out.

They know Trump's reputation for agreeing with the last person who has his ear and in the first term White House, officials vied to be that influential person. When that failed, they often leaked to the press in a bid to get their opinions heard.

With so many competing opinions, there could be even more leaks this time, despite the best efforts of the new chief of staff, Susie Wiles.

And so the key question for this administration is whether this surprisingly eclectic group will be able to hash things out and produce the best possible result. Or if the cabinet will be like a middle school brawl of eager students battling and obstructing each other in a bid to be teacher's pet with no clear principles to guide them.

The lack of cohesion already on display has some analysts alarmed, particularly on national security. "There is no consensus in the new administration when it comes to how China is viewed," says Richard Haass, who worked in the Bush administration and is now president emeritus of the Council on Foreign Relations. "One can anticipate ongoing struggles over American policy and more than a little inconsistency."

For now, Trump's desires reign supreme. But the president knows that in two short years America will hold midterm Congressional elections and the conversation will shift fast to the future. The Republican train will leave the station, and President Trump will be left standing on the platform.

He'll still have sway, and an awful lot of money that will give him some power over the succession, but the conversation will move on and the courtiers will be vying to become ruler themselves.

TikTok is resuming services to its 170 million users in US after President-elect Donald Trump said he would issue an executive order to give the app a reprieve when he takes office on Monday.

On Saturday evening, the Chinese-owned app stopped working for American users, after a law banning it on national security grounds came into effect.

Trump, who had previously backed a ban of the platform, promised on Sunday to delay implementation of the law and allow more time for a deal to be made. TikTok then said that it was in the process of "restoring service".

Soon after, the app started working again and a popup message to its millions of users thanked Trump by name. In a statement, the company thanked the incoming president for "providing the necessary clarity and assurance" and said it would work with Trump "on a long-term solution that keeps TikTok in the United States".

TikTok CEO Shou Chew is expected to attend Trump's inauguration Monday.

Posting on Truth Social, a social media platform he owns, Trump said on Sunday: "I'm asking companies not to let TikTok stay dark! I will issue an executive order on Monday to extend the period of time before the law's prohibitions take effect, so that we can make a deal to protect our national security."

TikTok's parent company, Bytedance, previously ignored a law requiring it to sell its US operations to avoid a ban. The law was upheld by Supreme Court on Friday and went into effect on Sunday.

It is unclear what legal authority Trump will have to delay the implementation of a law that is already in effect. But it expected that his government will not enforce the ban if he issues an executive order.

It's an about-face from his previous position. Trump had backed a TikTok ban, but has more recently professed a "warm spot" for the app, touting the billions of views he says his videos attracted on the platform during last year's presidential campaign.

For its part, President Joe Biden's administration had already said that it would not enforce the law in its last hours in office and instead allow the process to play out under the incoming Trump administration.

But TikTok had pulled its services anyway on Saturday evening, before the swift restoration of access on Sunday.

The short-form video platform is wildly popular among its many millions of US users. It has also proved a valuable tool for American political campaigns to reach younger voters.

Under the law passed last April, the US version of the app had to be removed from app stores and web-hosting services if its Chinese owner ByteDance did not sell its US operations.

TikTok had argued before the Supreme Court that the law violated free speech protections for its users in the country.

The law was passed with support from both Republicans and Democrats in Congress and was upheld unanimously by Supreme Court justices earlier this week.

The issue exposes a rift on a key national security issues between the president-elect and members of his own party. His pick for Secretary of State, Marco Rubio, had vocally supported the ban.

"TikTok extended the Chinese Communist Party's power and influence into our own nation, right under our noses," he said last April. But he seemed to defer to the president-elect when a journalist asked if he supported Trump's efforts to restore the ban.

"If I'm confirmed as secretary of State, I'll work for the president," he told Punchbowl media last week.

After Trump intervened on Sunday morning, Senate Intelligence Committee Chair Tom Cotton, a Republican senator from Arkansas, broke with Trump by saying that any company that helps TikTok stay online would be breaking the law.

"Any company that hosts, distributes, services, or otherwise facilitates communist-controlled TikTok could face hundreds of billions of dollars of ruinous liability under the law, not just from DOJ, but also under securities law, shareholder lawsuits, and state AGs," he wrote on social media.

An executive order that goes against the law could be fought in court.

Several states have also sued the platform, opening up the possibility to TikTok being banned by local jurisdictions, even if it is available nationally.

Although the platform went live again on Sunday for existing users, the question of whether third-parties - hosting platforms or app stores like Google or Apple - could support TikTok in the US remains murky, says University of Richmond law professor Carl Tobias. The app had been removed from those stores in anticipation of the ban.

"It is murky," he told the BBC.

In a post on Truth media, Trump promised to shield companies from liability, opening the door to TikTok being available on Apple and Google again.

"The order will also confirm that there will be no liability for any company that helped keep TikTok from going dark before my order," the president-elect said on Truth Social Sunday.

But during the Supreme Court hearings, Solicitor General Elizabeth Prelogar was adamant that an executive order cannot change the law retroactively.

"Whatever the new president does, doesn't change that reality for these companies," Justice Sonia Sotomayor said during the hearings.

"That's right," Prelogar said.

Professor Tobias said that the law does include a provision that would allow the president to postpone the ban for up to 90 days, if he can show that the company is making substantial progress on alleviating national security issues. But, he said, it's not clear whether those conditions have been met.

"The best thing Trump could do is work with Congress, and not potentially be in violation of the law or have any questions left hanging," he said.

"I don't know that we're going to know a whole lot more until we see that executive order."

Thousands of mostly female demonstrators took to the streets of Washington DC on Saturday to rally against President-elect Donald Trump two days ahead of his inauguration.

The People's March - previously known as the Women's March - has taken place every year since 2017.

A coalition of groups organised the movement with the stated aim of confronting "Trumpism", according to its website. Smaller protests against Trump were held in New York City and on the other side of the country in Seattle.

The rallies coincide with Trump's arrival to the nation's capital for a series of weekend events in the lead-up to his swearing-in ceremony on Monday.

Saturday's People's March in Washington DC drew smaller numbers than its predecessors.

Organisers had expected 50,000 people. About 5,000 turned up.

The protesters gathered at three parks before marching to the Lincoln Memorial for the rally.

The groups behind the march are described on its website as holding "intersecting identities" and having "varied issue-based interests" with different causes such as climate change, immigration and women's rights.

Organisers said they aimed to confront Trump by "drawing on past successes and effective strategies against autocrats".

A small group of Trump supporters were at the Washington Monument on Saturday. Noticing the men in red Make America Great Again hats, one People's March leader with a megaphone approached chanting: "No Trump, no KKK."

One of the men, Timothy Wallis, told the Associated Press news agency his friends had just bought the Trump hats from a street vendor.

Mr Wallis, 58, of Pocatello, Idaho, said the People's March protesters had "every right" to demonstrate, though he said he was confused by the rancour.

"It's sad where we're at as a country," he said.

The first iteration of the People's March came together after Trump defeated Democratic presidential nominee Hillary Clinton in 2016.

Women called for a protest the day after Trump's first inauguration and hundreds of thousands responded.

The movement spread beyond the nation's capital with millions of women across the US carrying signs railing against the Republican president and sporting pink knit "pussy hats" - a reference to a leaked tape in which Trump had bragged about grabbing women's genitals.

The Women's March remained a key part of the so-called resistance to Trump's agenda in the years that followed.

But none of the subsequent marches have been on the same scale.

Trump, meanwhile, was due to arrive in Washington DC later on Saturday to begin his inaugural festivities with a private event featuring fireworks at his golf club in the Virginia suburbs.

Women who gathered in Washington to join the People's March told the BBC they had a variety of motivations.

One protester, Brooke, said she wanted to show her support for abortion access.

"I'm really not happy with the way our country's voted," she said. "I'm really sad that our country's leaned towards a president that's already failed us once and that we did not nominate a female candidate."

Another woman, Kayla, said it's a mix of emotions that brought her out to the streets of the nation's capital.

"Honestly, I'm just mad, I'm sad, I'm overwhelmed," she said.

Susie came in from the San Francisco area to demonstrate with her sister, Anne, who lives nearby. They both attended the Women's March after Trump's first inauguration and came back in their "pussy hats".

Susie recalled the crowds of people in 2017. She said she hoped people would still take to the streets against Trump's policies.

"This time the stakes are higher," she said. "Trump has been emboldened. He's got the billionaire class and the tech class bowing down."

Anne also said she recognised the protesters are "out of touch" with a lot of America. Trump won all seven swing states and the popular vote last November.

But she added: "We're still here, and we will resist."

Holly Honderich and Alex Lederman contributed to this reporting

The US Supreme Court has upheld a law that bans TikTok in the US unless its China-based parent company ByteDance sells the platform by this Sunday.

TikTok had challenged the law, arguing it would violate free speech protections for the more than 170 million users it says it has in the US.

But that argument was rejected unanimously by the nation's highest court, meaning TikTok must now find an approved buyer for the US version of the app or face removal from app stores and web hosting services.

The White House said it would fall to incoming President Donald Trump's administration, which takes office on Monday, to enforce the law. Trump vowed to make a decision in the "not too distant future".

TikTok CEO Shou Zi Chew, who is expected to attend Trump's inauguration with other high-profile guests, said he wanted to thank the incoming president for his commitment to work with the app and keep it available in the US.

Both Democratic and Republican lawmakers voted to ban the video-sharing app last year, over concerns about its links to the Chinese government. TikTok has repeatedly stated it does not share information with Beijing.

Passed in April last year, the law allows TikTok owner ByteDance until 19 January 2025 to sell the US version of the platform to a neutral party to avert an outright ban.

It would mean that from Sunday, Apple and Google will no longer offer the app to new users or provide any security updates to current users - which could kill it off eventually.

ByteDance has vowed not to sell TikTok and said it planned to shut US operations of the app on Sunday unless there is a reprieve.

The Supreme Court ruled without any dissenting opinion that the law did not violate the US Constitution's First Amendment protection of free speech.

The justices affirmed a lower court's decision that upheld the statute after it was challenged by ByteDance.

"There is no doubt that, for more than 170 million Americans, TikTok offers a distinctive and expansive outlet for expression, means of engagement, and source of community," the Supreme Court said.

"But Congress has determined that divestiture is necessary to address its well-supported national security concerns regarding TikTok's data collection practices and relationship with a foreign adversary."

Following the Supreme Court ruling, White House press secretary Karine Jean-Pierre said in a statement that President Joe Biden's position on TikTok had been clear for months: "TikTok should remain available to Americans, but simply under American ownership or other ownership that addresses the national security concerns identified by Congress in developing this law."

But due to the "sheer fact of timing", she added, the president recognised "actions to implement the law simply must fall to the next administration, which takes office on Monday".

On Friday, Trump posted on his social media platform Truth Social: "The Supreme Court decision was expected, and everyone must respect it.

"My decision on TikTok will be made in the not too distant future, but I must have time to review the situation. Stay tuned!"

He also revealed he had spoken to China's President Xi Jinping and discussed TikTok, among other issues.

In December Trump said he had a "warm spot" for the app as it helped him with young voters in the 2024 election.

Trump's comments mark a U-turn on his stance in his first term as president when he aimed to enact a similar ban through an executive order.

Content creators, who have been posting farewells to their followers ahead of the looming ban, have been speaking to the BBC about how it could affect their livelihood.

"I went from being a waiter to being able to own a home and it all started with TikTok," says Drew Talbert, who has more than five million followers.

Kalani Smith has more than three million followers and calls the ban "a slap in the face".

"I was homeless before TikTok and lived in the back of my car. Using TikTok propelled me to where I'm at now," he says.

"Everyone is praying for some sort of miracle - it feels like the government has turned their backs on us."

Kelley Heyer who created the viral Apple dance to a Charli XCX song, says: "The government taking away TikTok is essentially the government taking away jobs from millions of people."

The ban comes at a time of heightened concern in the US about Chinese espionage.

Cybersecurity firms have suggested that the app is capable of collecting users' data beyond what they look at on TikTok.

US Attorney General Merrick Garland said authoritarian regimes should not have "unfettered access" to Americans' data and that the decision prevented China from "weaponising TikTok to undermine America's national security".

China enacted a law in 2017 that compels Chinese nationals living abroad to co-operate with its intelligence apparatus.

But Beijing has denied it pressures companies to collect information on its behalf and criticised the ban. TikTok has repeatedly stressed it has not been asked for its data.

The app argued the law endangers free speech and would hit its users, advertisers, content creators and employees. TikTok has 7,000 US employees.

Noel Francisco, lawyer for TikTok and ByteDance, told the Supreme Court during arguments that the app was "one of America's most popular speech platforms", and said the law would require it to "go dark" unless ByteDance sold the app.

Posting on TikTok after the ruling, the app's CEO said: "This is a strong stand for the First Amendment and against arbitrary censorship.

"We are grateful and pleased to have the support of a president [Trump] who truly understands our platform."

24 April 2024: Biden signs bipartisan TikTok bill, which gave Chinese parent company, ByteDance, six months to sell its controlling stake or be blocked in the US.

7 May 2024: TikTok files a lawsuit aiming to block the law, calling it an "extraordinary intrusion on free speech rights".

2 August 2024: The US government files a lawsuit against TikTok, accusing the social media company of unlawfully collecting children's data and failing to respond when parents tried to delete their children's accounts.

6 December 2024: TikTok's bid to overturn a law which would see it banned or sold in the US from early 2025 is rejected by a federal appeals court.

27 December 2024: President-elect Donald Trump asks the US Supreme Court to delay the upcoming ban while he works on a "political resolution".

10 January 2025: The Supreme Court's nine justices hear from lawyers representing TikTok and content creators that the ban would be a violation of free speech protections for the platform's more than 170 million users in the US.

17 January 2025: The US Supreme Court upholds the law that could lead to TikTok being banned within days over national security concerns.

19 January 2025: The deadline for TikTok to sell its US stake or face a ban. TikTok has indicated it will "go dark" on this day.