The White House said it is preparing additional “major sanctions” against Russia in response to Alexei Navalny’s death, with National Security Council spokesperson John Kirby saying the new package would be unveiled on Friday. He declined to detail them or share how they would expand on the already stiff measures the US and its allies have put on Russia.

Mr Kirby said only that the sanctions, which coincide with the second anniversary of Russia’s invasion of Ukraine, will be “specifically supplemented with additional sanctions regarding Mr Navalny’s death”.

Since Alexei Navalny’s death, about 400 people have been detained across Russia as they tried to pay tribute to him with flowers and candles, according to OVD-Info, a group that monitors political arrests.

Authorities cordoned off some of the memorials to victims of Soviet repression across the country that were being used as sites to leave makeshift tributes to Navalny. Police removed the flowers at night, but more keep appearing.

Kremlin spokesperson Dmitry Peskov said police were acting “in accordance with the law” by detaining people paying tribute to Navalny.

Over 60,000 people have submitted requests to the government asking for Navalny’s remains to be handed over to his relatives, OVD-Info said.

In her speech on Monday to the European Union’s Foreign Affairs Council, Yulia Navalnaya urged EU leaders not to recognize the results of next month’s presidential election in Russia, to sanction more of Vladimir Putin’s allies, and to help Russians who flee the country.

A copy of her remarks was released Tuesday by Navalny spokesperson Kira Yarmysh.

Joe Biden issued a blistering critique of Donald Trump’s Truth Social post on Navalny’s death, saying, “Why does Trump always blame America? (Russian president Vladimir) Putin is responsible for Navalny’s death. Why can’t Trump just say that?”

The US president and other western leaders have blamed Mr Putin for Alexei Navalny’s death, as has Nikki Haley, who trails far behind Mr Trump as his sole remaining rival for the Republican presidential nomination.

The Kremlin has denied involvement in Navalny’s death and said Western claims that Mr Putin was responsible are unacceptable.

Former US president Donald Trump said that Alexei Navalny was “a very brave man” who probably should not have returned to Russia, without assigning any blame for the Russian opposition leader’s unexpected death.

“Navalny is a very sad situation, and he is a very brave, he was a very brave guy because he went back. He could have stayed away,” Mr Trump said during a town hall interview with Fox News in South Carolina.

“And, frankly, he probably would have been a lot better off staying away and talking from outside of the country as opposed to having to go back in, because people thought that could happen and it did happen. And it’s a horrible thing,” he said.

Mr Trump - who has expressed admiration for Russian president Vladimir Putin both during his 2017-2021 White House tenure and afterward - continued to compare himself to Navalny, implying that they both had faced politically motivated prosecutions.

“But it’s happening in our country too,” Mr Trump said. “We are turning into a communist country in many ways. And if you look at it - I’m the leading candidate. I get indicted.”

On Sunday, he wrote in a Truth Social post that Navalny’s death in an Arctic penal colony last week had made him “more aware of what is happening” in the United States. Trump did not elaborate, but he has frequently dismissed the 91 criminal charges against him as politically motivated, a claim prosecutors deny.

Our Washington Bureau Chief Eric Garcia writes:

Upon the news of Russian opposition leader Alexei Navalny’s death, House Speaker Mike Johnson denounced Vladimir Putin.

“As Congress debates the best path forward to support Ukraine, the United States and our partners must be using every means available to cut off Putin’s ability to fund his unprovoked war in Ukraine and aggression against the Baltic states,” he said in a statement.

Of course, Johnson’s words would hold much more weight if he had actually put through the aid package for Ukraine, Israel and Taiwan that the Senate passed on the floor of the House of Representatives. Indeed, as the Senate labored late into the night on Monday and into the wee hours of Tuesday to pass that aid bill, Johnson summarily killed the bill because it did not address immigration at the US-Mexico border.

Despite his tough words, Johnson — a political neophyte only elected to the House in 2016, who became Speaker after three other candidates for the job faltered before him — has elected to appeal only to the most extreme elements of the GOP conference.

Critics like Alexei Navalny need support from the West against the “monster” Vladimir Putin, Alexander Litvinenko’s widow has said.

Marina Litvinenko’s husband, a prominent Putin critic and Russian defector, died in 2006 after becoming violently ill in London having been poisoned with radioactive polonium-210. A British inquiry found that Russian agents had killed Mr Litvinenko, probably with Putin’s approval, but the Kremlin denied any involvement.

He is among the many Kremlin political critics, turncoat spies and investigative journalists who have been killed or assaulted in a variety of ways over the years.

Ms Litvinenko branded Putin a “monster” and called on the West to help Russian opposition figures who are still alive. She told Sky News: “I am more thinking about people living in Russia, they have more dangerous lives, but they are still working on the outside.

“They are in need of support, and we are living here in the West, we need to support these people in Russia. We need to do everything to save the lives of these people, otherwise Putin’s regime will achieve its result.”

Before the sudden death of her husband Alexei Navalny in a grim Arctic prison last week, Yulia Navalnaya had always played down the suggestion that she would one day take over as leader of Russia’s opposition.

But on Monday, as the 47-year-old widow alternated between rage and grief, she gave a powerful speech signalling that she would be there to help lead a shell-shocked opposition – a job fraught with danger.

“I want to live in a free Russia, I want to build a free Russia,” said the mother-of-two in a video message. Stepping out of the shadow of her dead husband, she called on his supporters to “share the rage” and “stand” with her.

Filmed from a dimly lit room in an undisclosed location outside of Russia, the message in the video was both emotional and political.

My colleague Namita Singh reports: