Portrait of a Serbian partisan of the National Liberation Army in a field of wildflowers. The National Liberation Army and Partisan Detachments of Yugoslavia was Europe’s most effective anti-Nazi resistance movement. It was led by the Communist Party of Yugoslavia. The objectives of the National Liberation Army was to fight against the occupying Axis forces and to create a federal multi-ethnic communist state in Yugoslavia. However, the rival resistance movement, the Chetniks, were a Serbian nationalist, pro-monarchist movement and tensions between the two groups devolved into series of escalating battles between the two groups who both opposed Axis occupation, the Fascist Ustaše puppet state of Croatia and the Serbian puppet Government of National Salvation. The Chetniks initially garnered full Allied support, however, as the war raged on, their occasionally arbitrary and loose associations with the Axis occupiers in order to destroy their communist rivals caused the Allies to officially switch their support to the communist partisans. By late 1944, the total forces of the communist partisans numbered 650,000 men and women organized in four field armies and 52 divisions, which engaged in conventional warfare. By April 1945, they numbered over 800,000 and the communist party, led by Marshal Josip Broz Tito, would win the post-war Yugoslavian elections. Vojvodina, Yugoslavia (Serbia). August 1944.