Soviet espionage in the United States

Espionage against the United States by Soviet intelligence agencies

As early as the 1920s, the Soviet Union, through its GRU, OGPU, NKVD, and KGB intelligence agencies, used Russian and foreign-born nationals, as well as Communists of American origin, to perform espionage activities in the United States, forming various spy rings. Particularly during the 1940s, some of these espionage networks had contact with various U.S. government agencies. These Soviet espionage networks illegally transmitted confidential information to Moscow, such as information on the development of the atomic bomb. Soviet spies also participated in propaganda and disinformation operations, known as active measures, and attempted to sabotage diplomatic relationships between the U.S. and its allies.

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