In April - August 1991 Azerbaijan’s Special Purpose Police Units of the Ministry of Internal Affairs of Azerbaijan (OMON) along with the Soviet Internal Security Forces (ISF) and army divisions organized and perpetrated a large-scale military operation named “Ring” (“Koltso”) deporting thousands from the Armenian villages located both in Artsakh and Armenia. The operation was carried out by a special scheme; Armenian villages were being surrounded by Soviet ISF and army divisions respectively, after which the OMON forces were breaking into the villages, looting, killing, terrorizing the Armenians, forcing them to leave their homes "voluntarily", giving up their properties under the pretext of "passport check regime".