Russian President Vladimir Putin said Russia was changing its nuclear deterrence doctrine so that an attack by a non-nuclear state backed by a nuclear-armed ally would now be viewed as a "joint attack.

Vladimir Putin sent a chilling message to the West, warning them that giving into Ukraine's latest demand would lead to a nuclear war.Speaking to group of senior officials, the Kremlin leader pledged to change Russia's nuclear doctrine and threatened to use nuclear weapons if it was attacked by any state with conventional weapons,