US President Donald Trump and his Ukrainian counterpart Volodymyr Zelensky clashed in the White House on Friday over the need to reach a settlement in the war with Russia.

Trump scolded Zelensky as they sat in the Oval Office, asking him to be more "grateful," saying, "You are not in a position to tell us how to feel."

He also addressed his Ukrainian counterpart, saying, “Your people are very brave, but either you make a deal or we will withdraw, and if we withdraw, you will fight to the end.”

"I don't think it will be pretty," he added. "You will fight to the end, but you have no bargaining chips."

US Vice President J.D. Vance, sitting next to them, also attacked Zelensky, saying he had "disrespected" Americans.

Zelensky appeared to try to respond, but was interrupted.

The extraordinary confrontation came after Trump said Ukraine would have to make "concessions" to end its war with Russia, which launched a large-scale invasion of its neighbor three years ago.

"There is no deal without compromise," the US president said. "So there will certainly be compromises, but I hope they will not be as big as some people think."

But Zelensky, who showed Trump pictures of war atrocities, said there was "no compromise with a killer on our territory," referring to President Vladimir Putin.

He added that "crazy Russians" had deported Ukrainian children and committed war crimes during their three-year invasion of his country.

Trump fumed, saying, "You don't act like you're grateful at all. That's not nice."

"You are risking the lives of millions of people, you are risking World War III, and what you are doing is deeply disrespectful to the country, to this country," he added.

The confrontation came after a friendly start to the meeting between the two presidents.

"I think President Trump is on our side," Zelensky said.

He added that he would speak with the US president about the "vital" need for what he called a US "safety net" for any peacekeeping force to ensure a potential truce.

Trump alarmed Kiev and European allies with his sudden shift in US policy, backing away from the idea of supporting Ukraine until Russian forces were driven out of its territory, and presenting himself as a mediator between Putin and Zelensky.

The US president revealed in the Oval Office that he had "spoken several times" with Putin recently, while he had previously only revealed the long call between them earlier in February.

Trump told Zelensky that the truce was "relatively close."