Washington Post: US warns Russia against using nuclear weapons for months

For several months, U.S. President Joe Biden's administration has been sending private messages to Moscow about "grave consequences" that would follow Russia's use of nuclear weapons, The Washington Post reported on Sept. 22, citing unnamed U.S. officials.

The Biden administration decided to keep those warnings deliberately vague, "so the Kremlin worries about how Washington might respond," according to The Washington Post.

The Washington Post wrote that it's not clear if the U.S. has sent any messages after Russian President Vladimir Putin's speech about partial mobilization on Sept. 21, in which he said Russia would use all means at its disposal to defend the country's territorial integrity.