Russian President Vladimir Putin told the US and its NATO allies Wednesday that any attack on Russia with conventional weapons would likely provoke retaliation with nuclear weapons and that an attack by Ukraine that is supported by a nuclear power will bring retribution on both countries, Reuters reported.

The announcement denotes a radical departure in Russia’s nuclear doctrine – one that was consistent from the Cold War till the present – that Russia would never exercise a first strike nuclear option. The decision to revise that nuclear doctrine is Putin’s response to NATO’s continued insistence that Ukraine should be authorized to fire Western missiles into Russia

Publicly, Putin told a meeting of Russia’s Security Council that the change was a result of rapidly evolving global military threats to Russia.

The Russian president, who has a similar command and control function over nuclear weapons as that of the president of the United States, underscored one key point in his declaration. "It is proposed that aggression against Russia by any non-nuclear state, but with the participation or support of a nuclear state, be considered as their joint attack on the Russian Federation," Putin said.

"The nuclear triad remains the most important guarantee of ensuring the security of our state and citizens, an instrument for maintaining strategic parity and balance of power in the world," he continued.

Russia will consider the use of nuclear weapons "upon receiving reliable information about the massive launch of aerospace attack vehicles and their crossing of our state border, meaning strategic or tactical aircraft, cruise missiles, drones, hypersonic and other aircraft."

Russia has the largest nuclear arsenal in the world. With the United States, the two world powers have 88 percent of all nuclear warheads. The war in Ukraine has dragged on for two-and-a-half years and Ukraine is running out of the men and materiel to continue the war. Western intelligence has pegged Ukrainian losses at 80,000 dead, though that is considered by many to be a conservative estimate. NATO intervention could stall or preclude defeat and Ukrainian President Volodymyr Zenlenskyy has been encouraging more direct involvement from the US and the UK.