Ustaše is a Croatian terrorist organization who ruled Croatia during German occupation during World War II. The Party was formed in 1928 after the assassination of Stjepan Radić who was leading the Croatian Peasant Party.
The primary concern of the Ustasha was extermination of Serbs. The Ustasha pogrom was summarized in Mile Budak slogan: one third of Serbs to be killed, one third to be converted, and one third to be expelled. This was realized in most cruel ways, using mass slaughter and organizing competitions in slaughter of innocent women and children at Jasenovac.
The Ustashe also adopted Nazi Germany's anti-Semitic stance and policies. The Ustashe deported or killed a significant portion of the Jewish population in the territories it occupied.