Newsweek has broken down how Moscow, Beijing, London, New York, Los Angeles, Tokyo and Paris would be affected if any of these cities were targeted by a W88 exploding in an airburst dropped from 2,080 feet from the ground, according to NUKEMAP, a resource created by by Alex Wellerstein, a professor and historian of nuclear technology.

Russia said it tested a nuclear-powered cruise missile and torpedo, two of its experimental weapons, in recent days.

Putin announced successful Poseidon nuclear drone testing as President Donald Trump urged Russia to end the Ukraine war instead of testing missiles on Monday.

"We do not see anything that would give rise to the hypothesis of any substantive work going on there," Rafael Grossi says.

Three days after announcing a test of the nuclear-powered Burevestnik missile, Moscow said on Wednesday it also tested Poseidon, a nuclear-capable underwater drone. The second nuclear weapon test in just a week comes as the talks with the US stalled over Moscow’s reluctance to ceasefire in Ukraine.