Russian President Vladimir Putin’s dramatic claim on Thursday to have added an array of unstoppable weapons to its already vast nuclear arsenal has alarmed arms control advocates, and sparked new talk of a Cold War-style arms race between the two rival powers.

Putin, in a nationally televised speech coming less than three weeks before a March 18 presidential election, described at least four new weapons, including new long-range cruise missile powered by a small nuclear reactor that supposedly can fly “indefinitely”; a new hyper-glide vehicle that can bob and weave around radars; and an underwater drone armed with a massive nuclear warhead that could be floated to U.S. shores.