Military counterintelligence within the Soviet Armed Forces was controlled by the nonmilitary Soviet secret police throughout the history of the USSR (1922 to 1991). Military counterintelligence departments of the Soviet Armed Forces existed in all larger military formations, each called a Special Department or third department/section. The staff of the Special Department would usually establish a secret network of informants. TGU (ТГУ КГБ СССР, 3 ГУ КГБ СССР ('third')) functionaries were responsible for protection of the military units and of important servicemen (e.g. commanding officers) against activities of foreign military attaché offices/diplomats.

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