Russian President Vladimir Putin has warned that NATO risks a nuclear conflict if it sends troops to aid Ukraine, ramping up pressure on Kyiv’s U.S. and European allies just as his own forces go on the offensive.

"There’s been talk of sending NATO military forces to Ukraine,” Putin said Thursday in his annual address to the Federal Assembly of lawmakers and top officials. "We remember the fate of those who sent their contingents to our country before and this time the consequences for the potential interventionists will be far more tragic.”

The U.S. and Europe "must understand that we also have weapons that can hit targets on their territory and that all this really threatens a conflict with the use of nuclear weapons, and therefore the destruction of civilization,” Putin said. He listed new Russian strategic weapons that are entering military service, including Sarmat intercontinental ballistic missiles capable of carrying nuclear warheads.