Armenian–Azerbaijani war (1918–1920)
The Armenian-Azerbaijani war (1918–1920)[a] was a conflict that took place in the South Caucasus in regions with a mixed Armenian-Azerbaijani population, broadly encompassing what are now modern-day Azerbaijan and Armenia. It began during the final months of World War I and ended with the establishment of Soviet rule.
For other conflicts between Armenia and Azerbaijan, see Armenian–Azerbaijani war (disambiguation).
The conflict took place against the backdrop of the Russian Civil War and the partition of the Ottoman Empire. Mutual territorial claims, made by the newly formed Azerbaijan Democratic Republic and Republic of Armenia, led to their respective support for Azerbaijani and Armenian militias in the disputed territories. Armenia fought against Azerbaijani militias in the Erivan Governorate of the former Russian Empire, while Azerbaijan fought Armenian claims to the Karabakh region. The war was characterized by outbreaks of massacres and ethnic cleansing (such as the March Days, the September Days, the Shusha massacre, and more broadly, the Massacres of Azerbaijanis in Armenia), which changed the demographics of the region.
Hostilities broadly came to an end when the Soviet's 11th Army invaded and occupied both Azerbaijan and Armenia.
Aftermath
Sovietization of Azerbaijan, April 1920
In early April 1920, Republic of Azerbaijan was in a very troubled condition. In the west the Armenians still controlled large parts of territory claimed by Azerbaijan; in the east, local Azerbaijani communists were rebelling against the government; and to the north the Russian Red Army was steadily moving southward, having defeated Denikin's White Russian forces.
On 27 April 1920, the government of the Azerbaijan Democratic Republic received notice that the Soviet Army was about to cross the northern border and invade Azerbaijan. Faced with such a difficult situation, the government officially surrendered to the Soviets, but many generals and local Azerbaijani militias kept resisting the advance of Soviet forces and it took a while for the Soviets to stabilize the newly proclaimed Azerbaijan Soviet Socialist Republic, headed by leading Azerbaijani Bolshevik Nariman Narimanov.
While the Azerbaijani government and army were in chaos, the Armenian army and local Armenian militias used the opportunity to assert their control over parts of Azerbaijani territory, invading Shusha, Khankendi, and other important cities. By the end of April, Armenian forces were controlling most of western Azerbaijan, including all of Karabakh and surrounding areas. Other occupied areas included all of Nakhichevan and much of the Kazakh-Shamshadin district. In the meantime, Armenian communists attempted a coup in Armenia, but ultimately failed.