The PS-84 had flown with Aeroflot primarily as a passenger transport before World War II. When Germany attacked the Soviet Union in 1941 many of the PS-84s were taken into military use and redesignated the Lisunov Li-2 in 1942. The military models were equipped with a 7.62 mm (.30 in) ShKAS machine gun, and later with a 12.7 mm (.50 in) UBK heavy machine gun. The aircraft were used for transport, partisan supply, bombing, and as ambulance aircraft. A version designated Li-2VV ("Vojenny Variant" = military variant) had a redesigned nose for extra defensive armament and could carry up to four 250 kg (551 lb) bombs under the wings. Smaller bombs could be carried inside the fuselage and thrown out of the freight hatch by the crew.