President Donald Trump meets with Ukrainian President Volodymyr Zelenskyy during the United Nations General Assembly on Tuesday in New York. (AP Photo/Evan Vucci)

UNITED NATIONS (AP) — President Donald Trump said Tuesday that he believed Ukraine could win back all territory lost to Russia, a dramatic shift from the U.S. leader’s repeated calls for Kyiv to make concessions to end the war.

Trump posted on social media soon after meeting with Ukrainian President Volodymyr Zelenskyy on the sidelines of the United Nations General Assembly gathering of world leaders.

“I think Ukraine, with the support of the European Union, is in a position to fight and WIN all of Ukraine back in its original form,” Trump wrote. “With time, patience, and the financial support of Europe and, in particular, NATO, the original Borders from where this War started, is very much an option.”

The strengthened support from Trump, if it sticks, is a huge win for Zelenskyy, who has urged the American president to keep up the pressure on Russian President Vladimir Putin to end his war. It was a departure from Trump’s previous suggestions that Ukraine would never be able to reclaim all the territory that Russia has occupied since seizing the Crimean Peninsula in 2014.

That had disheartened Zelenskyy, Europeans and Ukrainians and called into question the U.S. commitment to U.N. principles of sovereignty and territorial integrity. But now, Trump’s view of the battlefield coincides more with Ukraine’s, Zelenskyy said.

“Trump is a game changer by himself,” Zelenskyy told reporters after their meeting.

Trump, going back to his 2024 campaign, insisted he would quickly end the war, but his peace efforts appear to have stalled following a diplomatic blitz last month, when he held a summit with Putin and a White House meeting with Zelenskyy and European allies.

Trump has acknowledged, including in his U.N. speech to world leaders, that he thought a resolution to this conflict would be “the easiest” because he has had a good relationship with Putin. Trump said he is open to imposing more sanctions on Russia and urged Europe to join in.

“Russia has been fighting aimlessly for three and a half years a War that should have taken a Real Military Power less than a week to win,” Trump wrote on social media. “This is not distinguishing Russia. In fact, it is very much making them look like ‘a paper tiger.'”

In his speech to the General Assembly, Trump said the war in Ukraine was making Russia “look bad” because it was “supposed to be a quick little skirmish.”