Republicans have shown a virtually united front in praising the White House following US President Donald Trump and Vice-President JD Vance's public row in the Oval Office with Ukrainian President Volodymyr Zelensky.

Senator Lindsey Graham suggested Zelensky should resign, adding that Friday's altercation had imperilled future US military support for Kyiv.

The extraordinary row culminated in Zelensky being asked to leave the White House without signing a deal with the US that would have jointly developed Ukraine's valuable minerals.

On Saturday, Zelensky enjoyed a much warmer reception from UK Prime Minister Keir Starmer in Downing Street, a day ahead of a meeting with King Charles.

The Ukrainian leader also made a plea on Saturday to the US to "stand more firmly" with Kyiv, adding that he was ready to sign the minerals deal with Trump, but wished for defined security guarantees.

Trump has suggested that Ukraine should concede territory to Russia to end its invasion and has opened peace talks between Washington and Moscow.

The American president has also warned Russia that he will impose high tariffs and further sanctions if President Vladimir Putin fails to end the "ridiculous" war.

Before leaving for Florida after the Oval Office clash with Zelensky, Trump told reporters that the Ukrainian leader had "overplayed his hand".

"Either we're going to end it or let him fight it out, and if he fights it out, it's not going to be pretty," Trump said. "Because without us, he doesn't win."

While Democrats said they were horrified by the showdown with a US ally, the majority of Republicans in Washington backed Trump.

"What I saw in the Oval Office was disrespectful, and I don't know if we can ever do business with Zelensky again," said Senator Graham, a longtime advocate for Ukraine aid and a foreign policy hawk, as he left the White House on Friday.

"The question for me is, 'is he redeemable in the eyes of Americans?' Most Americans witnessing what they saw today would not want Zelensky to be their business partner, including me, and I've been to Ukraine nine times since the war started."

Alabama Senator Tommy Tuberville posted on X on Saturday: "The best thing President Trump has done so far is kick that Ukrainian weasel out of the WH."

Tennessee Senator Bill Hagerty posted on X: "The United States of America will no longer be taken for granted."

But other Republican members of Congress were less enthused.

Mike Lawler of New York called the meeting "a missed opportunity for both the United States and Ukraine".

Don Bacon of Nebraska said it was "a bad day for America's foreign policy".

"Ukraine wants independence, free markets and rule of law. It wants to be part of the West. Russia hates us and our Western values. We should be clear that we stand for freedom," he said in a statement.

Neither Republican directly criticised Trump or Vance, who first quarrelled with Zelensky during the meeting.

Democrats, meanwhile, lambasted the White House.

"Trump and Vance are doing Putin's dirty work," Senate Minority Leader Chuck Schumer said.

Senator Chris Coons said Zelensky deserved better.

"We owe him our thanks for leading a nation fighting on the front lines of democracy - not the public berating he received at the White House," he posted on X.