Ukrainian President Volodymyr Zelensky on Monday called for "real, lasting peace" this year as European leaders gathered for a summit in Kyiv on the third anniversary of the war in Ukraine.

"We have to win peace through strength and wisdom and unity," Zelensky told Ukraine's backers in Kyiv.

He vowed at a press conference later that Russia "will not win".

EU Commission chief Ursula von der Leyen also warned that despite opening talks with the United States on how to end the conflict, Vladimir Putin was not about to back down.

"Putin is trying harder than ever to win this war on the ground. His goal remains Ukraine's capitulation," she said.

Russia said it would halt the attack only if a deal could be reached that "suits" its interests, and accused Europe of wanting to prolong the fighting.

Earlier on Monday, President Xi Jinping held a phone conversation with Putin and said China is happy to see efforts by Moscow and others to defuse the crisis in Ukraine, adding that China and Russia will support each other and achieve common development. (AFP)