Russia will also consider a conventional attack against it by a state without nuclear weapons but supported by a nuclear power as a "joint attack," according to the new doctrine. Before, the doctrine dictated Russia would use nuclear weapons only in ...

He declared that a conventional attack by any nation supported by a nuclear power will be considered a joint attack on Russia.

A decree signed by the Russian leader, though long-planned, came days after President Biden authorized the use of U.S.-supplied long-range missiles by Ukraine for strikes inside Russia.