The People's Commissariat for Internal Affairs was the interior ministry and secret police of the Soviet Union from 1934 to 1946. The agency was formed to succeed the Joint State Political Directorate (OGPU) secret police organization, and thus had a monopoly on intelligence and state security functions. The NKVD is known for carrying out political repression and the Great Purge under Joseph Stalin, as well as counterintelligence and other operations on the Eastern Front of World War II. The head of the NKVD was Genrikh Yagoda from 1934 to 1936, Nikolai Yezhov from 1936 to 1938, Lavrentiy Beria from 1938 to 1946, and Sergei Kruglov in 1946.
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