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. The decision to change Russia's official nuclear doctrine is the Kremlin's answer to a reported decision by the administration of U.S. President Joe Biden to allow Ukraine to fire American long-range missiles deep into Russia. The updated doctrine, which outlines the threats which would make Russia's leadership consider a nuclear strike, said an attack with conventional missiles, drones or other aircraft could be considered to meet these criteria.