The Kremlin on Sept. 26 emphasized that President Vladimir Putin’s revisions to Russia’s nuclear weapons doctrine should serve as a warning to Western nations, making clear that involvement in attacks on Russia would carry serious repercussions.

President Vladimir Putin warned the West on Wednesday that Russia could use nuclear weapons if it was struck with conventional missiles, and that Moscow would consider any assault on it supported by a nuclear power to be a joint attack.

The threat, outlined in a revision of Moscow's nuclear doctrine, was clearly aimed at discouraging the West from allowing Ukraine to strike Russia with longer-range weapons and appears to significantly lower the threshold for the possible use of Russia's nuclear arsenal.