At the beginning of the MGB, the Fourth Directorate was designed as a proto-terrorist force to combat the anti-Soviet underground, nationalist formations, and hostile elements. However, Viktor Abakumov dissolved this department in 1946, but kept the main players in a Special Service group so that they could continue with the same pattern of violence that the Fourth Directorate was known for. The group was also ultimately dissolved in 1949. Upon the destruction of the Fourth Directorate as a terrorist group, the department was transitioned into Transportation Security. It was responsible for the preparation and security of mobilization and transport. The department was also responsible for counterintelligence and surveillance operations within their transport programs.