Addressing lawmakers and other members of the country's elite, Putin, 71, repeated his accusation that the West was bent on weakening Russia, and he suggested Western leaders did not understand how dangerous their meddling could be in what he cast as Russia's own internal affairs.

He prefaced his nuclear warning with a specific reference to an idea, floated by French President Emmanuel Macron on Monday (February 26), of European NATO members sending ground troops to Ukraine - a suggestion that was quickly rejected by the United States, Germany, Britain and others.