This is according to the Financial Times.
The documents in question outline a lower threshold for the use of tactical nuclear weapons than previously acknowledged by Russia, comprising 29 classified military files from 2008 to 2014.
Despite the age of these documents, experts suggest their continued relevance to modern Russian military doctrine.
The exercise materials reveal that Russia's Eastern Military District has simulated various scenarios involving a Chinese invasion. These exercises offer a rare glimpse into Russia's perception of its nuclear arsenal as a key element of its defense strategy, illustrating preparations for potential nuclear first strikes in certain combat scenarios, reports indicate.
One hypothetical scenario detailed in the exercises envisions a Chinese attack, with Russia, referred to as the "Northern Federation" in the war game, considering a tactical nuclear response to halt the advancement of the "South" and its second wave of invasion forces.