President Donald Trump and Ukraine's President Volodymyr Zelenskyy following a meeting at Mar-a-Lago. ALEX BRANDON / AP

US President Donald Trump said on Sunday, December 28, that a deal was closer than ever to ending Russia's invasion of Ukraine, but reported no apparent breakthrough on the flash point issue of territory after new talks with the warring countries' leaders.

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 end the war that has killed tens of thousands of people since February 2022.

In a pre-New Year's diplomatic sprint, Trump brought Ukrainian President Volodymyr Zelensky to Florida, where the two met with top aides over lunch, a day after Russia unleashed major new attacks on residential areas of the capital Kyiv.

Much like when Zelensky last met Trump in October, Russian President Vladimir Putin also spoke shortly beforehand by telephone with the US leader, who immediately insisted that Moscow was "serious" about peace despite the assault.