Once the Kingdom of Yugoslavia was conquered by German forces in World War II, all of Bosnia was ceded to the Nazi puppet regime, the Independent State of Croatia (NDH) led by the Ustaše. The NDH leaders embarked on a campaign of extermination of Serbs, Jews, Romani as well as dissident Croats, and, later, Josip Broz Tito's Partisans by setting up a number of death camps. The regime systematically and brutally massacred Serbs in villages in the countryside, using a variety of tools. The scale of the violence meant that approximately every sixth Serb living in Bosnia and Herzegovina was the victim of a massacre and virtually every Serb had a family member that was killed in the war, mostly by the Ustaše. The experience had a profound impact in the collective memory of Serbs in Croatia and Bosnia. An estimated 209,000 Serbs or 16.9% of its Bosnia population were killed on the territory of Bosnia and Herzegovina during the war.