In April 1941 , Yugoslavia was occupied by Germany and Italy . Following the invasion the territory , parts of Croatia , Bosnia and Herzegovina , and the region of Syrmia were incorporated into the Independent State of Croatia ( NDH ) , a Nazi-backed puppet state . Parts of Dalmatia were annexed by Italy , and the northern Croatian regions of Baranja and Međimurje by Hungary . The NDH regime was led by Ante Pavelić and ultranationalist Ustaše . NDH was trying to establish such an internal structure that would be consistent with that of the Third Reich and fascist Italy so its authorities introduced racial laws against Jews , Roma and Serbs many of whome were imprisoned in concentration camps . In the same time , antifascist Croats were targeted by the regime as well . The number of Croats killed in the NDH is estimated to be approximately 200,000 , either by Ustaše , as members of the resistance movement , or as Axis collaborators . Chetniks killed between 18,000 and 32,000 Croats in whole of Yugoslavia . Furthermore , it is estimated that Ustashe regime systematically murdered somewhere between 200,000 and 340,000 Serbs
200,000 and 340,000 Serbs
Persecution of Serbs in the Independent State of Croatia
Croatia