NEW YORK — Has Donald Trump suddenly converted to being a fervent Ukraine supporter?

The question quickly dominated chatter Tuesday on the sidelines of the U.N. General Assembly in New York after Trump caught officials off guard with his most pro-Ukraine statement to date — a bold assertion that Kyiv can not only win its war against Russia, but also take back every inch of territory it’s lost.

The Truth Social post, published directly after the U.S. president met with his Ukrainian counterpart, Volodymyr Zelenskyy, was remarkable for two reasons: First, it contradicted his previous assertions that Ukraine can never hope to prevail over its larger foe. Secondly, it flew in the face of his administration’s prior view of how the Ukraine war should end, i.e. with a negotiated settlement in which Kyiv concedes territory to Russia.

EU officials trying to make sense of the apparent shift were caught between elation and skepticism, pointing out that Trump frequently changes his position — and may well do so again after a persuasive call with another leader, a reality that has made it all the more difficult for leaders to craft a response to the ongoing war and recent provocations from Moscow in European airspace far away from Ukraine.

Yet the immediate reaction from the delegation was tempered delight at the U.S. president’s sharp new tone.

“It’s the hardest one so far,” quipped one EU official on site in New York, referring to the pro-Ukraine nature of Trump’s post. “But he’s always one Putin call away from doing something not great.”

Trump offered some insight into how his mindset has shifted during a sit-down with France’s Emmanuel Macron during which he voiced disillusionment with Russian President Vladimir Putin. “I thought that was going to be the easiest one [war to stop] because of my relationship with Putin but unfortunately that relationship didn’t mean anything,” the U.S. president said.

Trump hit the same note in his formal address to the U.N. assembly earlier on Tuesday, saying that Putin’s failure to win his war against Ukraine was “not making Russia look good.” And he doubled down later in the day by answering “yes” when asked if NATO countries should shoot down Russian aircraft that violate their airspace, as has become increasingly frequent.

“I welcome the comments a few hours ago by the president of the United States, underscoring the progressive weakening of the Russian economy,” said Macron. “And I welcome seeing that the American president believe in Ukraine’s ability not just hold on, but to impose respect for its rights.”

For the Europeans, who have spent months trying to convince Trump that Putin bears full responsibility for the war, the apparent change of heart also came as something of a vindication of their own efforts.

Speaking to reporters outside the U.N. Security Council building, Europe’s top diplomat Kaja Kallas appeared to welcome Trump’s post as showing a change of heart. “He’s made a very strong statement that we hadn’t heard before so it really shows we are in the same understanding,” she said.

The post may also cheer European Commission President Ursula von der Leyen, who’s come under fire in recent months for being too accommodating of Trump, namely for having agreed to a U.S.-EU trade deal that was widely panned as a “humiliation” for Brussels.

Now, her approach looks like it might have a chance of paying off, at least as far as Ukraine is concerned. Meeting with Trump a few hours before his Truth Social post, von der Leyen stuck to her formula, saying “Trump is absolutely right” on the need for Europe to divest from Russian energy. “We’re on it,” she pledged.

Von der Leyen’s relationship with Trump has also evolved dramatically since he was first sworn in, said an EU official who was granted anonymity to speak about EU-Washington relations. The European Commission president is now in frequent phone contact with the U.S. president, using the calls to alert him to, among other things, Russia’s attack on the EU mission in Ukraine as well as the issue of Ukraine’s children abducted by Russia.

Trump had a “very in-depth” conversation with von der Leyen about the EU’s latest round of sanctions against Russia on Tuesday, with the U.S. president showing particular interest in measures targeting Chinese assets.

“We’re just seeing the product of time and again Europe said we’ll do X and we do X, whereas Russia says they will do A and they do Z,” said the EU official.

Amid the initial surprise and cheer, however, several EU officials and diplomats  voiced deeper skepticism that Trump’s post may be nothing more than an attempt to goad Putin — one that won’t bring about any real change in U.S. policy.

Indeed, after months of trying to convince Trump to hit Russia’s economy with tariffs or sanctions, hope for any U.S. buy-in is fading in Europe. And faith in Trump’s words — however encouraging they may be — is in vanishingly short supply.

“Fortunately but also unfortunately for us, what Trump says on a Monday is not what he said on a Tuesday,” said an ally to French President Emmanuel Macron.