President Donald Trump on Tuesday said NATO countries should shoot down Russian aircraft if they enter their airspace.

The comments came as Trump met with Ukrainian President Volodymyr Zelenskyy on the sidelines of the United Nations General Assembly in New York.

Pressed on whether the U.S. would back up NATO allies in such a situation, Trump said “it depends on the circumstance.”

Poland and Romania reported violations of their airspace earlier this month by Russian aircraft, prompting NATO to scramble fighter jets in response. Estonia on Friday said three Russian jets entered its airspace, which Russia has denied.

Polish Foreign Minister Radek Sikorski, who had been critical of Trump’s approach to Russian President Vladimir Putin in peace negotiations, responded quickly to Trump’s comments that NATO allies should shoot down Russian drones in their airspace.

“Roger that,” Sikorski wrote on X.

NATO’s Secretary General Mark Rutte on Tuesday reaffirmed the group’s commitment to defend allied territory but stopped short of saying any Russian aircraft that violates allied airspace would be shot down.

“Decisions on whether to engage intruding aircraft, such as firing upon them, are, of course, taking in real time, are always based on available intelligence regarding the threat posed by the aircraft, including questions we have to answer like intent, armament and potential risk to Allied forces, civilians or infrastructure,” Rutte said.

In his speech to the U.N. General Assembly on Tuesday, Trump criticized Russia for its ongoing war in Ukraine.

“It’s not making Russia look good. It’s making them look bad,” Trump said.

Trump said the United States is prepared to enact severe tariffs on Russia should Moscow not be ready to make a peace deal, a threat he’s made for weeks.

But he said other countries need to pull back on buying Russian oil and energy products “otherwise we’re all wasting a lot of time.”

“Europe has to step it up. They can’t be doing what they’re doing. They’re buying oil and gas from Russia while they’re fighting Russia. It’s embarrassing to them,” Trump said.

Ukraine’s Zelenskyy said he supported the idea when he met with Trump later Tuesday.

European Commission President Ursula von der Leyen, in a bilateral meeting with Trump, said she wants Europe to abandon its use of Russian energy by 2027 or earlier.

“President Trump is absolutely right on it,” she said. “We have reduced already massively the gas supply from Russia, completely gotten out of Russian coal and massively also reduced the oil supply. But there’s still some coming to the European continent.”

“We want to get rid of it,” she said.

Trump said he believed targeting Russia’s economy would help lead to the end of the war.

“After getting to know and fully understand the Ukraine/Russia Military and Economic situation and, after seeing the Economic trouble it is causing Russia, 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 on his social media platform after his bilateral meeting with Zelenskyy. “Ukraine would be able to take back their Country in its original form and, who knows, maybe even go further than that!” he added.

ABC News’ Hannah Demissie and Morgan Winsor contributed to this report.