 The German forces in the rear ( mostly Waffen @-@ SS and Einsatzgruppen units ) were to operate in conquered territories to counter any partisan activity in areas they controlled , as well as to execute captured Soviet political commissars and Jews . On 17 June , Reich Main Security Office ( RSHA ) chief Reinhard Heydrich briefed around thirty to fifty Einsatzgruppen commanders on " the policy of eliminating Jews in Soviet territories , at least in general terms . " While the Einsatzgruppen were assigned to the Wehrmacht 's units , which provided them with supplies such as gasoline and food , they were controlled by the RSHA . The official plan for Barbarossa assumed that the army groups would be able to advance freely to their primary objectives simultaneously , without spreading thin , once they had won the border battles and destroyed the Red Army 's forces in the border area . 
