Russia will station tactical nuclear weapons in Belarus, President Vladimir Putin said on Saturday, sending a warning to NATO over its military support for Ukraine and escalating a standoff with the West.

Although not unexpected and while Putin said the move would not violate nuclear nonproliferation promises, it is one of the Russia's most pronounced nuclear signals since the beginning of its invasion of Ukraine 13 months ago.

The United States — the world's other nuclear superpower — has reacted cautiously to Putin's statement, with a senior administration official saying there were no signs Moscow planned to use its nuclear weapons.