Putin confirms Russia can use nukes against conventional arms attack

President Vladimir Putin issued a decree on Tuesday stipulating that Russia's military can use nuclear weapons in response to an attack involving only conventional weapons.

Russia can proceed with such an action if the initial attack poses a direct threat to the "existence of the state," according to the decree, posted on the Kremlin's website.

Russia can also use its nuclear arsenal in response to an attack against an ally, if such an attack involved a weapon of mass destruction, the decree said.

Putin reserves the right as president to make the final decision on whether to use a nuclear weapon, according to the decree.