Einsatzgruppen (German: "task forces" or "operating groups") was the name of a set of special mobile execution squads made ??up of members of the SS, SD and other members of the secret police of Nazi Germany. These death squads belonged to the SS and acted first, superficially, to the annexation of Austria in 1938 (Anschluss) and the invasion of Czechoslovakia (1939), and then fully and in Poland (1939) and the Union of Soviet socialist Republics (USSR) in 1941 as a special autonomous units.