Russian President Vladimir Putin said on Friday that he did not see the conditions for the use of nuclear weapons as set out in Russia’s nuclear doctrine, but he added that he could not rule out a change to the doctrine.

Putin was answering a question by Sergei Karaganov, an influential Russian analyst, who asked if Putin should hold a nuclear pistol to the temple of the West over Ukraine.

Karaganov last year proposed a limited nuclear strike on a NATO member in Europe to force the West to back off in the conflict over Ukraine and thus avert World War Three.