A decree signed by the Russian leader, though long-planned, came days after President Biden authorized the use of U.S.-supplied long-range missiles by Ukraine for strikes inside Russia.

President Vladimir Putin has updated Russia’s nuclear doctrine, two days after his American counterpart Joe Biden granted Ukraine permission to strike targets deep inside Russia with US-made weapons.

President Vladimir Putin on Tuesday signed a revised nuclear doctrine declaring that a conventional attack on Russia by any nation that is supported by a nuclear power will be considered a joint