The Soviet Union created the Nagorno-Karabakh Autonomous Region within Azerbaijan in 1924, when over 94 percent of the region's population was Armenian (see fig. 3). (The term Nagorno-Karabakh originates from the Russian for "mountainous Karabakh.") As the Azerbaijani population grew, the Karabakh Armenians chafed under discriminatory rule, and by 1960 hostilities had begun between the two populations of the region.

On February 20, 1988, Armenian deputies to the National Council of Nagorno-Karabakh voted to unify that region with Armenia (see Population and Ethnic Composition , this ch.; Nagorno-Karabakh and Independence, ch. 1). Although Armenia did not formally respond, this act triggered an Azerbaijani massacre of more than 100 Armenians in the city of Sumgait, just north of Baku. A similar attack on Azerbaijanis occurred in the Armenian town of Spitak. Large numbers of refugees left Armenia and Azerbaijan as pogroms began against the minority populations of the respective countries. In the fall of 1989, intensified interethnic conflict in and around Nagorno-Karabakh led Moscow to grant Azerbaijani authorities greater leeway in controlling that region. The Soviet policy backfired, however, when a joint session of the Armenian Supreme Soviet and the National Council, the legislative body of Nagorno-Karabakh, proclaimed the unification of Nagorno-Karabakh with Armenia. In mid-January 1990, Azerbaijani protesters in Baku went on a rampage against remaining Armenians and the ACP. Moscow intervened, sending police troops of the MVD, who violently suppressed the APF and installed Mutalibov as president. The troops reportedly killed 122 Azerbaijanis in quelling the uprising, and Gorbachev denounced the APF for striving to establish an Islamic republic. These events further alienated the Azerbaijani population from Moscow and ACP rule. In a December 1991 referendum boycotted by local Azerbaijanis, Armenians in Nagorno-Karabakh approved the creation of an independent state. A Supreme Soviet was elected, and Nagorno-Karabakh appealed for world recognition.

Data as of March 1994