Serbian collaborationist organizations the Serbian State Guard (SDS) and the Serbian Border Guard (SGS) reached a combined 21,000 men at their peak. The Serbian Volunteers Corps (SDK), the party militia of the fascist Yugoslav National Movement led by Dimitrije Ljotić, reached 9,886 men; its members helped guard and run concentration camps and fought the Yugoslav Partisans and the Chetniks alongside the Germans. In October 1941, the Serbian Volunteer Corps participated in the Kragujevac massacre, arresting and delivering hostages to the Wehrmacht. The members of the Serbian Volunteer Corps had to take an oath stating that they would fight to death against both Communists and Chetniks.
