American espionage in the Soviet Union and Russian Federation

The United States has conducted espionage against the Soviet Union and its successor state, the Russian Federation, using both human intelligence (HUMINT) and technical intelligence (TECHINT) methods throughout the Cold War and into the present day. American intelligence operations against the Soviet Union included recruiting agents within the Soviet government and military, constructing tunnels to tap communications lines, conducting aerial reconnaissance, and developing satellite imagery systems.

Source: Wikipedia — American espionage in the Soviet Union and Russian Federation (CC BY-SA 4.0)