 Before the war , Hitler issued the notorious Commissar Order , which called for all Soviet political commissars taken prisoner at the front to be shot immediately without trial . German soldiers both willingly and unwillingly participated in these mass killings . On the eve of the invasion , German soldiers were informed that their battle " demands ruthless and vigorous measures against Bolshevik <unk> , guerrillas , saboteurs , Jews and the complete elimination of all active and passive resistance . " Collective punishment was authorized against partisan attacks ; if a perpetrator could not be quickly identified , then burning villages and mass executions were considered acceptable reprisals . An estimated two million Soviet prisoners of war died of starvation during Barbarossa alone ; nothing was done for their survival . The famished prisoners of war were hardly able to walk by themselves . By the end of the war , 58 percent of all Soviet prisoners of war died in German captivity . 
