The NKVD (Narodny komissariat vnutrennikh del listen (info • help)) or People's Commisariat for Internal Affairs) was a government department which handled a number of the Soviet Union's affairs of state.
The NKVD is best known for the Main Directorate for State Security (GUGB), which came after the OGPU and the Cheka as the secret police agency of the Soviet Union, and which became KGB. Many think of the NKVD as a criminal group. This is mostly because of the activities of GUGB officers and investigators. The NKVD was also in charge of Stalin's foreign intelligence service and overseas 'special operations'. These NKVD sub-branches hired spies and gathered of political, military, and economic information from other countries. They also got rid of political enemies who lived outside of the Soviet Union and enforced Stalin's policies within Communist Party movements in other countries.
In addition to its state security and police functions, some of its departments handled other matters, such as transportation, fire guards, border guards (NKVD Border Troops), etc. These jobs were usually assigned to the Ministry of the Interior (MVD).