The Soviet Air Defence Forces (, voyska protivovozdushnoy oborony, voyska PVO, V-PVO, lit. Anti-Air Defence Troops; and formerly protivovozdushnaya oborona strany, PVO strany, lit. Anti-Air Defence of the Country) was the air defence branch of the Soviet Armed Forces. Formed in 1941, it continued being a service branch of the Russian Armed Forces after 1991 until it was merged into the Air Force in 1998. Unlike Western air defence forces, V-PVO was a branch of the military unto itself, separate from the Soviet Air Force (VVS) and Air Defence Troops of Ground Forces. During the Soviet period it was generally ranked third in importance of the Soviet services, behind the Strategic Rocket Forces and the Ground Forces. History Service during Second World War Preparations for creation of the air defence forces started in 1932, and by the beginning of Operation Barbarossa, June 1941, there were 13 PVO zones within the military districts. At the outbreak of war, air defence forces were in the midst of rearmament. Anti-aircraft artillery teams had few of the latest 37 mm automatic and 85 mm guns. Moreover, the troops were deficient in Yak-1s and MiG-3s; 46 percent of the fleet were obsolete aircraft. Increased rates of production were initiated to provide the troops with new equipment. In July 1941, the National Defence Committee took several measures to strengthen the forces guarding Moscow and Leningrad, Yaroslavl and Gorky industrial areas, and strategic bridges across the Volga. To this end, the formation of parts of the IA, IN, anti-aircraft machine gun and searchlight units were accelerated. A classic example of a major political organization of defence and industrial center was the defence of Moscow. It was carried out by the 1st Air Defence Corps and the 6th Fighter Aviation Corps PVO. As part of these formations at the beginning of German air raids had more than 600 fighters; more than 1,000 guns of small and medium calibers; 350 machine guns; 124 fixed anti-aircraft barrage balloons; 612 stations and 600 anti-aircraft searchlights. The presence of such large forces and their skilful management foiled enemy attempts to inflict massive air strikes. Only 2.6 percent of the total number of Axis aircraft flew in the outskirts of Moscow as a result of their efforts. Air defence forces defending Moscow destroyed 738 enemy aircraft. Assaults by the 6th Fighter Aviation Corps inflicted heavy blows, destroying 567 enemy aircraft on the ground.