Phoenix (US), Mar 3 (AP) President Donald Trump's senior aides and allies lashed out at Ukrainian leader Volodymyr Zelenskyy from Washington as he attended a European summit Sunday in London to rally international support for his military's fight against the Russian invasion.

Following Trump's lead, White House officials and Republicans in Congress used news show appearances to demand that Zelenskyy display more gratitude for US support and an openness to potential war-ending concessions to Russian President Vladimir Putin. Some suggested Zelenskyy should consider resigning even as Ukrainians rally around him.

But they offered little clarity as to what Zelenskyy and Ukraine could do after Friday's Oval Office meeting in which Trump and Vice President JD Vance berated him before canceling the signature of an economic agreement between Washington and Kyiv. The dispute leaves the future of that relationship in question, as well as the prospects for ending a conflict that began when the Kremlin invaded in February 2022.

White House national security adviser Mike Waltz, who while in Congress went to Ukraine during the first year of the war to meet Zelenskyy and once compared him to wartime British Prime Minister Winston Churchill, said Zelenskyy's behavior at the White House was “incredibly disrespectful”.

Asked about that Churchill-Zelenskyy comparison, Waltz noted that Churchill was voted out of office in the final months of World War II.

Churchill “was a man for a moment, but he did not then transition England into the next phase,” Waltz said. “And it's unclear whether President Zelenskyy, particularly after what we saw Friday, is ready to transition to Ukraine to an end to this war and to negotiate and have to compromise.” Waltz said a negotiated end to the war would involve territorial concessions from Ukraine as well as “Russian concessions on security guarantees," but he did not offer any more details about what Moscow would have to do.

House Speaker Mike Johnson echoed the suggestion that Zelenskyy may need to step aside.

“Either he needs to come to his senses and come back to the table in gratitude, or someone else needs to lead the country to do that,” Johnson said. "I mean, it's up to the Ukrainians to figure that out. But I can tell you that we are re-exerting peace through strength.” Trump's director of national intelligence, Tulsi Gabbard, said the contentious meeting has led to “a huge rift in the relationship” and she took issue with Zelenskyy telling Fox News afterward that he did not think he did anything wrong.

“There's going to have to be a rebuilding of any kind of interest in good faith negotiations, I think, before President Trump is going to be willing to reengage on this,” she said.

The coordinated campaign of pressure from Washington played out as Zelenskyy and European leaders came to terms with Trump's overhaul of U.S. foreign policy. British Prime Minister Keir Starmer said the United Kingdom would use 1.6 billion pounds ($2 billion) in export financing to supply 5,000 air defense missiles for Ukraine.

Support for Zelenskyy among congressional Republicans has been scant after the Oval Office meeting. But Alaska Senator Lisa Murkowski, one of the few GOP lawmakers willing to break with Trump publicly, criticised the Republican president's stance toward the Ukrainians.

“I know foreign policy is not for the faint of heart, but right now, I am sick to my stomach as the administration appears to be walking away from our allies and embracing Putin, a threat to democracy and US values around the world," Murkowski wrote on X on Saturday.

Senator James Lankford said it was inappropriate for senators to call for Zelenskyy to leave office and predicted that such a move would “spiral Ukraine into chaos right now”.

Others were more vocal in support of Zelenskyy.

Millions of Americans “are embarrassed, are ashamed," said Senator Bernie Sanders.

“Our job is to defend the 250-year tradition that we have of being the democratic leader of the world, not turn our backs on a struggling country that is trying to do the right thing,” Sanders said.

Waltz appeared on CNN's “State of the Union,'' Johnson, Sanders and Lankford were on NBC's ”Meet the Press," and Gabbard spoke on “Fox News Sunday”. (AP) SCY SCY