MOSCOW (AP) — Changes in Russia's nuclear doctrine are intended to discourage Ukraine's Western allies from supporting attacks on Russia, the Kremlin said Thursday. The Kremlin spokesman Dmitry Peskov told reporters that the revisions in the document announced by President Vladimir Putin are a “warning signal to those countries about the consequences in case of their involvement in an attack on our country with various assets, not necessarily nuclear ones.” In a strong, new warning to the West , Putin said Wednesday that any nation’s conventional attack on Russia that is supported by a nuclear power will be considered a joint attack on his country.

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. Speaking during Wednesday's Security Council meeting that discussed changes in the nuclear doctrine, Putin didn’t specify whether the modified document envisages a nuclear response to such an attack, but he emphasized that Russia could use nuclear weapons in response to a conventional assault posing a “critical threat to our sovereignty,” a vague formulation that leaves broad room for interpretation. Russia is making slow but steady gains in Ukraine as the conflict grinds through its third year, and the Kremlin is seeking to discourage stronger W.