Top Kremlin official Dmitry Medvedev issued a fiery nuclear warning to the U.S. after Ukrainian President Volodymyr Zelensky said officials in Moscow should learn where their nearest bomb shelter is if they don't end Russia's war.

Zelensky, in an interview with Axios, said U.S. President Donald Trump had given his explicit backing to Ukrainian strikes on Russian targets such as energy infrastructure and arms factories, and that if Kyiv receives more long-range American weaponry, then "we will use it".

"The Kiev drug addict said the Kremlin should know where a bomb shelter is so its occupants can hide when he uses long-range American weapons," Medvedev, who is deputy chairman to Russian President Vladimir Putin on the Kremlin's Security Council, and is himself a former president and prime minister of Russia, in a post on X.

"What the freak needs to know is that Russia can use weapons a bomb shelter won't protect against. Americans should also keep this in mind."

NATO-Russia Conflict

Tensions between Russia and U.S.-led NATO—both sides armed with devastating arsenals of nuclear weapons—have escalated sharply in recent weeks as Moscow's invasion of Ukraine thunders on, despite Trump's efforts to broker a peace deal. The potential for a direct NATO-Russia clash is increasing.

NATO allies have accused Russia of a series of serious violations of their airspace, allegations Moscow says lack evidence. In one such incident, Poland says it had to shoot down a dozen Russian drones that violated its airspace and threatened its security during an attack on neighboring western Ukraine.

Trump, speaking at a press conference alongside Zelensky during the United Nations General Assembly meeting in New York, said he thought NATO countries should shoot down Russian aircraft entering their airspace.

Trump: Ukraine Could Recapture All Land

He also posted to his Truth Social platform that, with NATO's support, Ukraine could win back all of the territory seized by Russia over the course of its full-scale invasion, launched in February 2022.

"Why not?" Trump wrote. "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. This is not distinguishing Russia. In fact, it is very much making them look like 'a paper tiger.'"

Trump continued: "When the people living in Moscow, and all of the Great Cities, Towns, and Districts all throughout Russia, find out what is really going on with this War, the fact that it’s almost impossible for them to get Gasoline through the long lines that are being formed, and all of the other things that are taking place in their War Economy, where most of their money is being spent on fighting Ukraine, which has Great Spirit, and only getting better, Ukraine would be able to take back their Country in its original form and, who knows, maybe even go further than that!"

Updated, 9/25/25, 8:30 a.m. ET: This article was updated with more information.