Russian nuclear submarines sailed off for drills in the Barents Sea and mobile missile launchers roamed snow forests Tuesday in Siberia after President Vladimir Putin ordered his nation’s nuclear forces put on high alert over tensions with the West over the invasion of Ukraine. Russia’s Northern Fleet said in a statement that several of its nuclear submarines were involved in exercises designed to “train maneuvering in stormy conditions.” It said several warships tasked with protecting northwest Russia’s Kola Peninsula, where several naval bases are located, would join the maneuvers. In the Irkutsk region of eastern Siberia, units of the Strategic