The First Nagorno-Karabakh War was an ethnic and territorial conflict that took place from February 1988 to May 1994, in the enclave of Nagorno-Karabakh in southwestern Azerbaijan, between the majority ethnic Armenians of Nagorno-Karabakh backed by Armenia, and the Republic of Azerbaijan with support from Turkey. As the war progressed, Armenia and Azerbaijan, both former Soviet republics, entangled themselves in protracted, undeclared mountain warfare in the mountainous heights of Karabakh as Azerbaijan attempted to curb the secessionist movement in Nagorno-Karabakh.
The enclave's parliament had voted in favor of uniting with Armenia and a referendum, boycotted by the Azerbaijani population of Nagorno-Karabakh, was held, in which a 99.89% voted in favor of independence with a 82.2% turnout. The demand to unify with Armenia began in a relatively peaceful manner in 1988; in the following months, as the Soviet Union disintegrated, it gradually grew into an increasingly violent conflict between Armenians and Azerbaijanis, resulting in ethnic cleansing, including the Sumgait (1988) and Baku (1990) pogroms directed against Armenians, and the Gugark pogrom (1988) and Khojaly Massacre (1992) directed against Azerbaijanis. Inter-ethnic clashes between the two broke out shortly after the parliament of the Nagorno-Karabakh Autonomous Oblast (NKAO) in Azerbaijan voted to unite the region with Armenia on 20 February 1988. The declaration of secession from Azerbaijan was the culmination of a territorial conflict. As Azerbaijan declared its independence from the Soviet Union and removed the powers held by the enclave's government, the Armenian majority voted to secede from Azerbaijan and in the process proclaimed the unrecognized Republic of Nagorno-Karabakh.
Full-scale fighting erupted in early 1992. Turkey sent mercenaries to fight for Azerbaijan and assisted in blockading trade to Armenia, including humanitarian aid. International mediation by several groups including the Conference for Security and Co-operation in Europe (CSCE) failed to bring an end resolution that both sides could work with. In early 1993, Armenian forces captured seven Azerbaijani-majority districts outside the enclave itself, threatening the involvement of other countries in the region. By the end of the war in 1994, the Armenians were in full control of the enclave, in addition to surrounding Azerbaijani territories, most notably the Lachin Corridor – a mountain pass that links Nagorno-Karabakh with mainland Armenia. A Russian-brokered ceasefire was signed in May 1994.
As a result of the conflict, approximately 724,000 Azerbaijanis were expelled from Armenia, Nagorno-Karabakh and the surrounding territories, while 300,000–500,000 Armenians living in Azerbaijan or Armenian border areas were displaced. After the end of the war and over a period of many years, regular peace talks between Armenia and Azerbaijan were mediated by the OSCE Minsk Group but failed to result in a peace treaty. This left the Nagorno-Karabakh area in a state of legal limbo, with the Republic of Artsakh remaining de facto independent but internationally unrecognized. Ongoing tensions persisted, with occasional outbreaks of armed clashes. Armenian forces occupied approximately 9% of Azerbaijan's territory outside the enclave until the Second Nagorno-Karabakh War in 2020.
Background
The territorial ownership of Nagorno-Karabakh today is heavily contested between Armenians and Azerbaijanis. The current conflict has its roots in events following World War I. Amid the dissolution of the Russian Empire in November 1917 and seizure of power by the Bolsheviks, the three main ethnic groups of the South Caucasus, Armenians, Azerbaijanis and Georgians, struggled to come to an agreement on the nature of political government in the region. An attempt at shared political authority in the form of the Transcaucasian Federation in the spring of 1918 came to naught in the face of an invasion by the forces of the Ottoman Empire. In May 1918, separate Armenian, Azerbaijani and Georgian national republics declared their formal independence from Russia.
Armenian–Azerbaijani war
Fighting soon broke out between the First Republic of Armenia and the Azerbaijan Democratic Republic in three regions in particular: Nakhchivan, Zangezur (today the Armenian provinces of Syunik and Vayotz Dzor) and Karabakh itself.