Leaked classified documents describe conditions under which Russia could use tactical nuclear weapons, according to the Financial Times. The files from 2008 and 2014 reportedly show that Moscow would potentially deploy the devices—which are designed for limited battlefield use but could still be many times more powerful than those dropped on Japan at the end of WWII—when certain criteria are met. They reportedly include conditions like a fifth of Russia’s strategic ballistic missile submarines being destroyed, the loss of 30 percent of its nuclear-powered attack subs, three or more cruisers being taken out, or even the loss of three airfields. A simultaneous attack on Russia’s main and reserve coastal command centers could also trigger a nuke strike, as could an enemy incursion into Russian territory. Russia could also use the bombs as a way of preventing the loss of battles or as a means of “stopping aggression.” Experts who reviewed the files told the FT they reveal a threshold for using tactical nuclear weapons that is significantly lower than the Kremlin has ever publicly acknowledged.