Top Washington officials suggested Sunday that Ukrainian leader Volodymyr Zelensky might have to step down if a peace deal is to be reached, underscoring President Donald Trump's stunning shift in approach to the war with Russia.

"We need a leader that can deal with us, eventually deal with the Russians, and end this war," National Security Advisor Mike Waltz told CNN.

"And if it becomes apparent that President Zelensky's either personal motivations or political motivations are divergent from ending the fighting in this country, then I think we have a real issue."

His remarks and those of other key Republicans follow Trump's dramatic turn against Zelensky during a contentious Oval Office meeting on Friday. 

The rare public spat — with Trump calling the Ukrainian "disrespectful" — resulted in Zelensky leaving the White House without the anticipated signing of a preliminary pact on sharing Ukrainian mineral rights.

Zelensky had tried, during the heated exchange, to say that Kyiv still needed security guarantees if it is to trust a peace deal with Moscow after a bitter three-year war sparked by the Russian invasion.

Significantly, given the uncertainty whether a deal can be salvaged, Trump on Sunday shared a reposting on his Truth Social platform arguing that the mineral agreement itself would provide the needed security.

"Trump ensures that Americans will be involved in Ukraine's mining industry," the message read. "This prevents Russia from launching an invasion, because attacking Ukraine would mean endangering American lives — something that would force the U.S. to respond."

'Arm of the Kremlin'

When Republican officials were asked on Sunday talk shows whether Putin could in fact be trusted, they instead suggested that Zelensky might pose the greater obstacle to peace.

"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," said House Speaker Mike Johnson.

"I mean, it's up to the Ukrainians to figure that out, but... we need President Zelensky to do what is necessary."

And Tulsi Gabbard, director of national intelligence, told "Fox News Sunday" that Zelensky had "created a huge rift in the relationship."

One Republican senator spoke out Sunday in defense of Zelensky, however.

Asked on NBC about calls for the Ukrainian to step down, James Lankford, a member of the Senate intelligence committee, replied, "I don't agree." 

"Quite frankly," he added, "I think that would spiral Ukraine into chaos right now trying to find who is the negotiator to bring an issue to peace."

Senior Democrats also pushed back angrily after Friday's diplomatic debacle.

"The White House has become an arm of the Kremlin," said Senator Chris Murphy, who has emerged as one of Trump's most outspoken critics.

"It appears America is trying to align itself with dictators," he said on CNN.

Secretary of State Marco Rubio insisted, however, that the White House was clear-eyed about Putin's Russia. 

"No one here is claiming Vladimir Putin is going to get the Nobel Peace Prize this year," he said on ABC.

But Rubio added that "you cannot end a war unless both sides come to the table."

"I'm not promising you it's possible," he added. "I'm not telling you it's 90 percent likely. I'm saying it's zero percent likely if we don't get them to a negotiating table."

European leaders have rallied around Ukraine, but the dizzying pace of events has left them struggling to make sense of what some fear could be the most tectonic change to Western security architecture since shortly after World War II.

Their latest cause for concern came late Saturday in a post on X from Elon Musk, the billionaire Trump supporter who has been given extraordinary powers to cut government spending.

To a post calling for the United States to withdraw from NATO and the United Nations, Musk responded simply, "I agree."

Trump has repeatedly pressed other NATO members to spend more on defense, and has often seemed to chafe at the multilateralism inherent in the UN approach.

He told an NBC journalist in December that he would "absolutely" consider leaving NATO if fellow alliance members weren't "paying the bills... (and) treating us fairly."

But on Sunday, NATO chief Mark Rutte said after Ukraine crisis talks in London that the United States remains committed to the alliance. He also announced that European countries will increase defense spending.

Of the UN, Trump said on 4 February that it has "great potential, and based on the potential we'll continue to go along with it, but they got to get their act together."

"It's not being well run, to be honest and they're not doing the job."