What countries have nuclear weapons, and where are they?

A U.S. Air Force jet performs a test drop of a B61-12 bomb in December 2021. That bomb can contain a nuclear warhead for use in wartime. Los Alamos National Laboratory

The Russian invasion of Ukraine has raised fears among the public about the use of nuclear weapons in Europe or against the United States. This level of concern has not been seen since the end of the Cold War.

NATO countries have been taken aback by Russian President Vladimir Putin’s implied threats to use nuclear weapons against “whoever interferes with us” in Ukraine, and his placement of additional nuclear officers on shifts under a “special regime of combat duty.”