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 Nation) was the air defence branch of the Soviet Armed Forces. It continued being a service branch of the Armed Forces of the Russian Federation from 1991 to 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.