 In June 1941 , Serbs in eastern Herzegovina rebelled against the authorities of the Independent State of Croatia ( Croatian : <unk> <unk> <unk> , NDH ) , an Axis puppet state established during World War II on the territory of the defeated Kingdom of Yugoslavia . As the NDH imposed its authority , members of the fascist Ustaše ruling party began a campaign of persecution against Serbs throughout the country . In eastern Herzegovina , the Ustaše <unk> a series of massacres and attacks against the majority Serb population commencing in the first week of June . Between 3 and 22 June 1941 , spontaneous clashes occurred between NDH authorities and groups of Serbs in the region . 
