WASHINGTON >> President Donald Trump and Vice President JD Vance berated President Volodymyr Zelenskyy of Ukraine on Friday in an explosive televised Oval Office shouting match that ultimately blew up plans to sign a rare minerals deal and signaled a dramatic break in relations between two wartime allies.

In a public confrontation unlike any seen between a U.S. president and foreign leader in modern times, Trump and Vance castigated Zelenskyy for not being grateful enough for U.S. support in its war with Russia and sought to strong-arm him into making a peace deal on whatever terms the Americans dictated.

With voices raised and tempers flaring, Trump threatened to abandon Ukraine altogether if Zelenskyy did not go along. After journalists were escorted out of the Oval Office, Trump canceled the rest of the visit, including a planned joint news conference and signing ceremony for the minerals deal.

“I have determined that President Zelenskyy is not ready for Peace if America is involved, because he feels our involvement gives him a big advantage in negotiations,” Trump wrote on social media. “I don’t want advantage, I want PEACE. He disrespected the United States of America in its cherished Oval Office. He can come back when he is ready for Peace.”

The White House later sent out Sen. Lindsey Graham, R-S.C., a close Trump ally, to tell reporters that Zelenskyy should consider stepping down. “He either needs to resign and send somebody over that we can do business with, or he needs to change,” Graham said on the White House driveway.

The confrontation left the state of affairs uncertain but provided a major boost to President Vladimir Putin of Russia, who has long sought to drive a wedge between Ukraine and its most important patron, the United States.

The president’s verbal assault on Zelenskyy was a remarkable display of anger and resentment toward the leader of a country that has been invaded by a larger power intent on eliminating it as an independent state. No president in memory has ever erupted at a visiting foreign leader in such a vituperous way on camera, not even enemies of the United States, much less a putative ally.

Talking over the Ukrainian leader, Vance told Zelenskyy that it was “disrespectful” for him to come to the Oval Office and make his case in front of the American news media and demanded that he thank Trump for his leadership. Trump jumped in and told the Ukrainian leader that “you’re not really in a good position right now” and that “you’re gambling with World War III.”

“You’re either going to make a deal, or we’re out,” Trump added. “And if we’re out, you’ll fight it out, and I don’t think it’s going to be pretty.”

Vance’s eagerness to assail Zelenskyy left many observers wondering whether it was a planned or impromptu tantrum. Vance has never been a supporter of Ukraine and said in 2022 that “I don’t really care what happens to Ukraine.”

After Vance began chastising Zelenskyy, it seemed to trigger Trump to join in.

The result, though, was the blowup of an economic deal that Trump had prioritized in recent days, a commitment by Ukraine to turn over rare mineral rights to repay U.S. military aid over the past three years. The future of that deal remained unclear.

Zelenskyy’s hurriedly arranged visit to Washington to sign that deal was meant to smooth over tensions with Trump, who just last week parroted Russian talking points by falsely claiming that Ukraine “started” the war and calling Zelenskyy a “dictator without elections.”

With Zelenskyy agreeing to the minerals deal, Trump seemed ready to make nice by telling reporters Thursday that he did not remember the dictator comment and expressing respect for the Ukrainian leader. He welcomed Zelenskyy at the door of the West Wing on Friday morning with an honor guard, and they shook hands politely but without evident warmth.

The encounter, though, quickly turned hostile shortly after they sat down in the Oval Office with journalists present. Zelenskyy, dressed in his usual dark, long-sleeved shirt, sought to explain the history of the war with Russia, noting that it went back to 2014 when Moscow first seized Crimea and occupied territory in eastern Ukraine and continued through Trump’s first term.

He also expressed skepticism of peace efforts mentioned by Vance. “What kind of diplomacy, JD, you are speaking about?” he asked. “What do you mean?”

Bristling, Vance replied: “I’m talking about the kind of diplomacy that’s going to end the destruction of your country.”

He then began assailing Zelenskyy. “I think it’s disrespectful for you to come into the Oval Office to try to litigate this in front of the American media,” Vance lectured. “You should be thanking the president for trying to bring an end to this conflict.”

He accused Zelenskyy of mounting a “propaganda tour” in the United States. “Do you think that it’s respectful to come to the Oval Office of the United States of America and attack the administration that is trying to prevent the destruction of your country?”

Zelenskyy tried to respond to Vance’s assertions and said that the United States could feel threatened by Russia some day. “You have a nice ocean and don’t feel now, but you will feel it in the future,” he said.

That set off Trump, who cut off Zelenskyy. “Don’t tell us what we’re going to feel,” he said, raising his voice. “You’re not in a good position. You don’t have the cards right now.”

“I’m not playing cards,” Zelenskyy replied. “I’m very serious, Mr. President. I’m the president in a war.”

“You’re gambling with World War III,” Trump retorted. “And what you’re doing is very disrespectful to the country, this country, that’s backed you far more than a lot of people said they should have.”

Vance jumped back in. “Have you said ‘thank you’ once this entire meeting? No.”