President Vladimir Putin has signed a new military doctrine that describes NATO's military buildup near the Russian borders as the top military threat amid Russia-West tensions over Ukraine.

The document released by the Kremlin on Friday maintains the provisions of the previous, 2010 edition of the military doctrine regarding the use of nuclear weapons. It says Russia could use nuclear weapons in retaliation to the use of nuclear or other weapons of mass destruction against it or its allies, and also in case of aggression involving conventional weapons that "threatens the very existence" of the Russian state.

For the first time, the new doctrine says that Russia could use precision weapons "as part of strategic deterrent measures." The document doesn't spell out conditions for their use.