Typically, NKVD Internal Troops were defensive in nature, although they played a particularly instrumental role during the Battle of Moscow, the Siege of Leningrad, and the Battle of Stalingrad where the 10th NKVD Rifle Division suffered almost 90% casualties during the battle. Large VV units also stayed in the rear to maintain order, fight enemy infiltrators and to guard key installations (such as the armament manufacturing complex at Tula, protected by the 156th NKVD regiment in 1941) and the railway installations guarded by the 14th Railway Facilities Protection Division NKVD.