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.

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

Russian President Vladimir Putin formally lowered the threshold for his country's use of nuclear weapons Tuesday, after the U.S. allowed Ukraine to strike inside Russia using American missiles.

The attack with an intermediate-range ballistic missile has spurred fears of a major escalation in the ongoing war and prompted Ukraine to request new air defenses.

Russian President Vladimir Putin makes a televised address, dedicated to a military conflict in Ukraine and in particular to Russia's launch of a hypersonic intermediate-range ballistic missile attack on a military facility in response to recent Ukrainian long-range strikes with Western weapons,