n 6 April 1941.
World War II (1941–45)
Once the kingdom of Yugoslavia was conquered by Nazi forces in World War II, all of Bosnia was ceded to the Nazi puppet regime, Independent State of Croatia. The Croat leaders embarked on a campaign of extermination of Serbs, Jews, Roma, Croats who opposed the regime, communists and large numbers of Josip Broz Tito's Partisans by setting up a number of death camps.
Many Serbs themselves took up arms and joined the Chetniks; a Serb nationalist movement that conducted operations against the Nazi forces and the partisans. The Chetniks were also known to persecute and murder non-Serbs and communist sympathizers. They committed many war crimes against Bosnian Muslims in Eastern Bosnia. On October 12, 1941 a group of 108 notable Muslim citizens of Sarajevo signed the Resolution of Sarajevo Muslims by which they condemned the persecution of Serbs organized by Ustaše, made distinction between Muslims who participated in such persecutions and whole Muslim population, presented informations about the persecutions of Muslims by Serbs and requested security for all citizens of the country, regardless of their identity. Later, many Bosnian Muslims served in the Waffen-SS units.
Starting in 1941, Yugoslav communists under the leadership of Josip Broz Tito organized their own multi-ethnic resistance group, the partisans, who fought against both Axis and Chetnik forces. On 29 November 1941 the Anti-Fascist Council of National Liberation of Yugoslavia with Tito at its helm held a founding conference in Jajce where Bosnia and Herzegovina was reestablished as a republic within the Yugoslavian federation in its Habsburg borders.
Military success eventually prompted the Allies to support the Partisans, but Tito declined their offer to help and relied on his own forces instead. All the major military offensives by the antifascist movement of Yugoslavia against Nazis and their local supporters were
