Russian President Vladimir Putin has 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 attack on his country.

Russian President Vladimir Putin on Tuesday approved an updated nuclear doctrine, saying that Russia could consider using nuclear weapons if it was subject to a conventional missile assault on it supported by a nuclear power.

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.