Unlike most other major directorates of the Soviet (and Russian) Defense Ministry, the secretive 12th GUMO was effectively invisible to public view during the Soviet period. The Directorate's history began at the end of the Second World War, when the First Main Directorate was established under the Soviet Council of Ministers to "coordinate work on atomic projects." Two years later a "special department" was set up in the Ministry of Defense to study the employment and effects of US nuclear weapons. After the first test of a Soviet nuclear weapon in 1949, the First Main Directorate and the MoD's special department were merged to form a main directorate "to provide centralized direction of testing, stockpiling, and operating nuclear weapons and . . . protection against nuclear weapons." This organization was the direct progenitor of today's 12th GUMO.
Military research and scientific test organizations as well as military units engaged in the immediate operation of nuclear munitions are subordinate to 12th GUMO. Tasks related to the elimination of intermediate and shorter range missiles and the limitation of strategic nuclear arms, the elimination of nuclear munitions and increasing the safety of the remaining ones also has been assigned to the Main Directorate in recent years.
The 12th GUMO maintains large central nuclear munitions depots filled with tactical, operational/strategic, and strategic nuclear weapons withdrawn from non-Russian areas of the former Soviet Union, or otherwise taken "off-line" and redeployed. In addition to units for transporting nuclear weapons, the 12th GUMO includes a variety of research, development, and support facilities over which it has exclusive control.The system for the protection of nuclear munitions is echeloned and generally extremely reliable. Access to them is multilayered, and it is virtually impossible for unauthorized individual to gain access to the warheads. The transport of nuclear munitions is also properly organized. Special security units are in a high state of readiness to thwart any attempt to seize them. To date there has not been a single loss from the nuclear arsenals. Potential vulnerabilities to criminal or terrorist groups are principally in the theft of nuclear weapons while in transport, which must be taken "into account in planning our actions on a day-to-day basis."