The nation of Yugoslavia was created in the aftermath of World War I, and it was mostly composed of South Slavic Christians, though the nation also had a substantial Muslim minority. This nation lasted from 1918 to 1941, when it was invaded by the Axis powers during World War II, which provided support to the Croatian fascist Ustaše (founded in 1929), whose regime carried out the genocide of Serbs, the Jews and of the Roma inside its territory through executions in concentration camps and other systematic mass crimes. The predominantly Serb Chetniks, a Yugoslav Royalist and Serbian nationalist movement and guerrilla force, engaged in mass crimes which are considered by several authors to constitute genocide of Muslims and Croats, while also supporting the instatement of a Serbian monarchy and Yugoslav federation. The Communist-led Yugoslav Partisans were able to appeal to all groups, including Serbs, Croats, and Bosniaks, and also engaged in mass killings. In 1945, the Federal People's Republic of Yugoslavia (FPRY) was established under Josip Broz Tito, who maintained a strongly authoritarian leadership that suppressed nationalism. After Tito's death in 1980, relations among the six republics of the federation deteriorated. Slovenia, Croatia and Kosovo desired greater autonomy within the Yugoslav confederation, while Serbia sought to strengthen federal authority. As it became clearer that there was no solution agreeable to all parties, Slovenia and Croatia moved toward secession. Although tensions in Yugoslavia had been mounting since the early 1980s, events in 1990 proved decisive. In the midst of economic hardship, Yugoslavia was facing rising nationalism among its various ethnic groups. By the early 1990s, there was no effective authority at the federal level. The Federal Presidency consisted of the representatives of the six republics, two provinces and the Yugoslav People's Army, and the communist leadership was divided along national lines.