In 1937 – 1938 NKVD conducted mass operations " for the destruction of espionage and sabotage contingents " ( known as National operations of NKVD ) among diaspora nationalities against both Soviet and foreign citizens ( resulting in arrest and usually execution ) , including an NKVD campaign against Germans , in fact indiscriminately targeting national minorities during the Great Terror . Concurrently all German and other diaspora national districts and schools in the Soviet Union except the Volga German ASSR and German schools within that republic were abolished
Great Terror
Great Purge
Germany–Soviet Union relations, 1918–1941