oblasts to nine new banovinas. The effect of Alexander's dictatorship was to further alienate the non-Serbs living in Yugoslavia from the idea of unity. Alexander was assassinated in Marseille, during an official visit in 1934 by Vlado Chernozemski, member of the IMRO. Alexander was succeeded by his eleven-year-old son Peter II and a regency council was headed by his cousin, Prince Paul. In August 1939 the Cvetković–Maček Agreement established an autonomous Banate of Croatia as a solution to Croatian concerns. World War II In 1941, in spite of Yugoslav attempts to remain neutral in the war, the Axis powers invaded Yugoslavia. The territory of modern Serbia was divided between Hungary, Bulgaria, the Independent State of Croatia, Greater Albania and Montenegro, while the remaining part of the occupied Serbia was placed under the military administration of Nazi Germany, with Serbian puppet governments led by Milan Aćimović and Milan Nedić assisted by Dimitrije Ljotić's fascist organization Yugoslav National Movement (Zbor). The Yugoslav territory was the scene of a civil war between royalist Chetniks commanded by Draža Mihailović and communist partisans commanded by Josip Broz Tito. Axis auxiliary units of the Serbian Volunteer Corps and the Serbian State Guard fought against both of these forces. The siege of Kraljevo was a major battle of the uprising in Serbia, led by Chetnik forces against the Nazis. Several days after the battle began the German forces committed a massacre of approximately 2,000 civilians in an event known as the Kraljevo massacre, in a reprisal for the attack. Draginac and Loznica massacre of 2,950 villagers in Western Serbia in 1941 was the first large execution of civilians in occupied Serbia by Germans, with Kragujevac massacre and Novi Sad Raid of Jews and Serbs by Hungarian fascists being the most notorious, with over 3,000 victims in each case. After one year of occupation, around 16,000 Serbian Jews were murdered in the area, or around 90% of its pre-war Jewish population during The Holocaust in Serbia. Many concentration camps were established across the area. Banjica concentration camp was the largest concentration camp and jointly run by the German army and Nedić's regime, with primary victims being Serbian Jews, Roma, and Serb political prisoners. During this period, hundreds of thousands of ethnic Serbs fled the Axis puppet state known as the Independent State of Croatia and sought refuge in German-occupied Serbia, seeking to escape the large-scale persecution and Genocide