In April 1941, Yugoslavia was occupied by Germany and Italy who created a puppet-state called the Independent State of Croatia (NDH) which was governed by the pro-Axis Ustasha organization. The Ustashas sought to create ethnically pure Greater Croatia by cleansing Serbs as well as Jews and Roma from its territory. The Ustashas regime systematically murdered around 300,000–350,000 Serbs, as a part of a genocide campaign. Approximately 100,000 people, primarily Serbs, Roma and Jews and others were murdered in Jasenovac concentration camp alone. The predominantly Serb Chetniks, a Yugoslav royalist and Serbian nationalist movement and guerrilla force, engaged in war crimes and ethnic cleansing of Muslims and Croats in order to establish Greater Serbia, while also supporting the reinstatement of a Serbian monarchy. Some historians view these crimes as constituting genocide. The most recent estimates on the number of Muslims and Croats deaths caused by the Chetniks in Croatia and Bosnia and Herzegovina range from 47,000 to 65,000. Following the victory of Yugoslav Partisans, who were led by Croatian communist Josip Broz Tito, the Ustashas and the Chetniks were defeated. Yugoslav communists abolished the monarchy and established one-party socialist republic and a federation governed by the League of Communists of Yugoslavia. Newly formed socialist Yugoslav state under Tito's benevolent dictatorship was made up of six socialist republics including SR Serbia and SR Croatia.