Putin is the primary decision-maker on the use of Russia's nuclear arsenal. The doctrine said any attack by a non-nuclear power supported by a nuclear power would be considered a joint attack, and that any attack by one member of a military bloc would be considered an attack by the entire alliance, it said.

President Vladimir Putin said on Thursday that the Ukraine war was escalating towards a global conflict after the United States and Britain allowed Ukraine to hit Russia with their weapons, and warned the West that Moscow could strike back.

This week's saber rattling has come during a period in which the war has passed 1,000 days and at a pivotal moment in the conflict between Moscow and Kyiv.