Palm Beach, Florida - President Donald Trump said Sunday that a deal was closer than ever to end Russia's invasion of Ukraine but reported no apparent breakthrough on the flashpoint issue of territory after a new round of talks.

Trump, who had promised a peace deal on day one of his nearly year-old presidency, said it would become clear within weeks whether it was possible to solve the conflict that has killed tens of thousands of people.

In a pre-New Year's diplomatic sprint, the 79-year-old welcomed Ukrainian President Volodymyr Zelensky, who described a peace plan as 95% complete despite Russia unleashing major new attacks a day before on Kyiv's residential areas.

Russian President Vladimir Putin also spoke shortly beforehand by phone with Trump, who immediately insisted that Moscow was "serious" about peace despite the assault.

"I really believe we're, Mr. President, probably closer than – far closer than – ever before with both parties," Trump said with Zelensky at his side in the tea room of his Mar-a-Lago estate.

"Everybody wants it ended," he insisted.

Zelensky looked on politely, only betraying the slightest look of disbelief as Trump told him that Putin, who ordered the February 2022 invasion that has included major attacks on infrastructure, "wants to see Ukraine succeed."

"President Putin was very generous in his feeling toward Ukraine succeeding, including supplying energy, electricity and other things at very low prices," the Republican claimed.

After their talks, Zelensky and Trump spoke jointly by phone with key European leaders, who have been particularly alarmed about any decisions that would embolden Russia. Joint talks could be held next month in Washington.

Trump acknowledged continued disagreement between Kyiv and Moscow on territory. The current plan, revised after weeks of intense US-Ukrainian negotiations, would stop the war at the current frontlines in the eastern Donbas region and set up a demilitarized area, while Russia has long demanded territorial concessions.

"It's unresolved, but it's getting a lot closer. That's a very tough issue, but one that I think will get resolved," Trump said.

Trump offered to address the Ukrainian parliament to promote the plan – an idea, however unlikely, that Zelensky quickly welcomed.

The Ukrainian leader's openness to the revised US plan marks Kyiv's most explicit acknowledgement yet of possible territorial concessions, although Ukrainians would need to vote in a referendum.

By contrast, Russia has shown no signs of compromise, as it sees hope in the grinding gains it has made over four years against tough Ukrainian defenses.

The Kremlin in its readout of talks between Putin and Trump called on Kyiv to make a "bold and responsible decision" and immediately withdraw troops from Donbas and cast European leaders as the impediment to Trump.

Trump and Putin agree that a "temporary ceasefire" would "merely prolong the conflict and risk a renewed escalation on the battlefield," Kremlin diplomatic advisor Yuri Ushakov said.

He said that Trump and Putin would speak again "promptly" after the Zelensky meeting, although there was no immediate news of a second call.