U.S. President Donald Trump meets with Ukrainian President Volodymyr Zelenskyy at the White House in Washington, D.C., U.S., Feb. 28. / REUTERS/Brian Snyder

Ukrainian President Volodymyr Zelenskyy's meeting with U.S. President Donald Trump ended in disaster on Feb. 28, after the two leaders traded verbal blows before the world's media at the White House over the war with Russia.

The visit by Zelenskyy was designed to help Ukraine convince the United States not to side with Russian President Vladimir Putin, who ordered the invasion of Ukraine three years ago.

Instead the Ukrainian leader disagreed sharply with Trump and Vice President JD Vance over the conflict, underlining how the change of administration in Washington has undermined Kyiv's attempts to maintain Western support for its war effort.

Vance stressed the need for diplomacy to resolve the biggest conflict in Europe since World War Two, while Zelenskyy countered that Putin could not be trusted in any negotiations.

Trump quickly took to Truth Social to accuse Zelenskyy of disrespecting the United States.

"I have determined that President Zelenskyy is not ready for Peace if America is involved," he wrote, using an alternative spelling of the leader's name. "He can come back when he is ready for Peace."

Zelenskyy left the White House early following the confrontation, without signing a much-vaunted deal between Ukraine and the United States over the joint development of natural resources.

The clash also undermines recent efforts by European leaders to convince Trump to provide security guarantees for Ukraine even if he has refused to deploy U.S. soldiers on Ukrainian soil.

Such guarantees are seen as crucial to deter Russia from future aggression.

"People are dying, you're running low on soldiers," Trump told Zelenskyy as they engaged in a remarkably blunt argument before reporters in the Oval Office.

Trump threatened to withdraw U.S. support from Ukraine.

"You're either going to make a deal, or we're out, and if we're out, you'll fight it out. I don't think it's going to be pretty," Trump told Zelenskyy.

"You don't have the cards. Once we sign that deal, you're in a much better position. But you're not acting at all thankful, and that's not a nice thing. I'll be honest. That's not a nice thing."

Zelenskyy openly challenged Trump over his softer approach toward Putin, urging him to "make no compromises with a killer."

Trump stressed that Putin wants to make a deal.

"You are gambling with World War Three," Trump told Zelenskyy at one point, urging him to be more thankful.

Vance interjected that it was disrespectful of Zelenskyy to come to the Oval Office to litigate his position, a point Trump agreed with.

"You didn't say thank you," Vance said. Zelenskyy, raising his voice, responded: "I said a lot of times thank you to American people."

Zelenskyy, who gained billions of dollars' worth of U.S. weaponry and moral support from the Biden administration for its fight against Russia, is facing a sharply different attitude from Trump. Trump wants to quickly wind down the three-year war, improve ties with Russia and recoup money spent to support Ukraine.

"I hope I'm going to be remembered as a peacemaker," Trump said.

Earlier, Trump told Zelenskyy that his soldiers have been unbelievably brave and that the United States wants to see an end to the fighting and the money put to "different kinds of use like rebuilding."

Trump has adopted a much less committed stance toward European security, a change in tone that has sent shockwaves across Europe and stoked fears in Kyiv and among its allies that it could be forced into a peace deal that favours Russia.

NO SECURITY GUARANTEES IN DEAL

The agreement negotiated in recent days would open Ukraine's vast mineral wealth to the United States but does not include explicit American security guarantees for Ukraine, a disappointment for Kyiv. Trump says the presence of Americans in business would serve as a form of guarantee.

How much the deal would be worth to the United States is not spelled out. Trump has said he expects to gain hundreds of billions of dollars. Zelenskyy has said he would not sign an agreement that would put his country in debt for generations.

Ukraine would contribute 50 percent of "all revenues earned from the future monetization of all relevant Ukrainian Government-owned natural resource assets" to a reconstruction fund jointly owned and managed by the United States and Ukraine.

The agreement does not specify how the funds would be spent, or identify specific assets it covers, though it says they would include deposits of minerals, oil and natural gas as well as infrastructure such as gas terminals and ports.