Armenian – Azerbaijani War The Armenian – Azerbaijani War , which started after the Russian Revolution , was a series of brutal and hard to classify conflicts in 1918 , then from 1920 to 1922 that occurred during the brief independence of Armenia and Azerbaijan and afterwards . Most of the conflicts did not have a principal pattern with a standard armed structure . The Ottoman Empire and British Empire were involved in different capacities : the Ottoman Empire left the region after the Armistice of Mudros but British influence continued until Dunsterforce was pulled back in 1920s . The conflicts involved civilians in the disputed districts of Kazakh - Shamshadin , Zanghezur , Nakhchivan and Karabakh . The use of guerrilla and semi - guerrilla operations were the main reasons for the high civilian casualties , which occurred during the nation - building activities of the newly established states . The reasons behind the conflict are still far from being resolved after nearly a century . The story of this campaign has very different perceptions ; according to Armenian historians , the First Republic of Armenia aimed to include Nakhchivan among the basic ( Eastern Armenia n ) territories of the Erivan Governorate , as well as the eastern and southern parts of the Elisabethpol Governorate . Background . The first clashes between the Armenians and Azeri s took place in Baku in February 1905 . Soon , the conflict spilled over to other parts of the Caucasus , and on August 5 , 1905 the first conflict between the Armenian and Azeri population of Shusha took place . Active stages . In the March 1918 , ethnic and religious tensions grew and the Armenian - Azeri conflict in Baku began . Musavat and Committee of Union and Progress parties were accused of Pan - Turkism by Bolsheviks and their allies . Armenian and Muslim militia engaged in armed confrontation , which resulted in heavy casualties . Many Muslims were expelled from Baku , or went underground . Meanwhile the arrest of General Talyshinski , the commander of the Azerbaijani division , and some of its officers all of whom arrived in Baku on March 9 , increased the anti - Soviet feelings among the city ' s Azeri population . On 30 March , the Soviets , based on the unfounded report that the Muslim crew of the ship " Evelina " was armed and ready to revolt against the Soviet , disarmed the crew which tried to resist This led to 3 - day fighting resulting in the death of up to 12 , 000 Azeris . Fight for Baku and Karabakh , 1918 – 1919 . At the same time the Baku Commune was involved in heavy fighting with the advancing Caucasian Ottoman Army in and around Ganja . Enver Pasha , the Ottoman Empire , began to move forward with the newly established Army of Islam . Major battles occurred in Yevlakh and Agdash , where the Turks routed and defeated Dashnak and Russian forces . Dunsterville ordered the evacuation of the city on September 14 , after six weeks of occupation , and withdrew to Iran ; most of the Armenian population escaped with British forces . The Ottoman Army of Islam and its Azeri allies , led by Nuri Pasha , entered Baku on September 15 and slaughtered between 10 , 000 - 20 , 000 Armenians in retaliation for the March massacre of Muslims . The capital of the Azerbaijan was finally moved from Ganja to Baku . However , after the Armistice of Mudros between the United Kingdom and the Ottoman Empire on October 30 , Turkish troops were substituted by the Triple Entente . Headed by British general W . Thomson , who had declared himself the military governor of Baku , 1 , 000 Commonwealth soldiers arrived in Baku on November 17 , 1918 . By General Thomson ' s order , martial law was implemented in Baku . The Armenian government tried several times to seize Shusha militarily . Beginning with 1918 , Republic of Mountainous Armenia was declared in the region . However throughout the summer of 1918 , Armenians in the mountainous Karabag region , under the leadership of Andranik Ozanian resisted the Ottoman 3rd army . After the Armistice , the Ottoman Empire began to withdraw its forces and Armenian forces under Andranik seized Nagorno - Karabakh . Armstice of Mudros brought General Adriank the chance to create a base for further expansion eastward and form a strategic corridor extending into Nakhchivan . In January 1919 Armenian troops advanced towards Shusha , captured and destroyed 9 Azeri villages on their way but eventually had to retreat . Just before the Armistice of Mudros was signed , Andranik was on the way from Zangezur to Shusha , to control the main city of the Karabakh . The Armenian government tried several times to seize Shusha militarily , before . In January 1919 , while Armenian troops advancing , the British military command ordered Andranik back to Zangezur , and gave him the assurances that this conflict can be solved with the Paris Peace Conference , 1919 . Andranik pulled back his units and British command at Baku gave the control to Khosrov bey Sultanov , a native of Karabakh , who was appointed the general - governor of Karabakh . He had three Armenian and three Azeri aide . Fight for Nakhchivan , 1919 – 1920 . In response to a border proposal by Sir John Oliver Wardrop , British Chief Commissioner in the South Caucasus , that would have assigned Nakhchivan to Armenia , Azeris of Nakhchivan revolted under the leadership of the local landowner Jafargulu Khan Nakhchivanski in December 1918 and declared the independent Republic of Aras , with its capital in Nakhchivan . The republic , which essentially subordinated to Azerbaijan , continued to exist until May 1919 , when Armenia advanced its troops led by Drastamat Kanayan into it to gain control over the region . They managed to capture the city of Nakhchivan in June 1919 and disestablish the Republic of Aras , but immediately clashed with regular Azerbaijani troops , which reinstalled Azerbaijan ' s control over the city in July . Azerbaijani troops led by former Turkish officer Khalil Bey successfully defended the town of Beiuk Vedi , twenty - six miles from the Armenian capital . On 10 August 1919 , the Armenians were forced to sign a peace treaty . Fighting resumed in March 1920 , echoing the Armenian revolt in Karabakh , and continued until the Sovietization of Nakhchivan in 1920 when the 11th Red Army , now including former Azerbaijan Democratic Republic troops , effectively defeated the Armenians in Ordubad and Shahtakhty . Despite this , Armenia continued unsuccessful incursions into Nakhchivan until November 1920 . Fight for Karabakh , early 1920 . The largest Armenian - Azeri ethnic clashes in Shusha took place on March – April 1920 . On the night from March 21 – 22 , 1920 when the Azeris were celebrating Spring Equinox ( Novruz Bayram ) , the Armenians of Karabakh began to revolt and organized a surprise attack . On March 22 – 26 , 1920 , the Shusha pogrom took place , which resulted many Armenian deaths and the destruction of the Armenian quarter of the city . Sovietization of Azerbaijan , April 1920 . In early April 1920 the Republic of Azerbaijan was in a very troubled situation . In the west , the Armenians still controlled large parts of territory claimed by Azerbaijan ; in the east , the local Azeri 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 April 27 , 1920 the government of the Azerbaijan Democratic Republic received notice that the Soviet army was about to cross the northern border and invade the ADR . Faced with such a difficult situation , the government officially surrendered to the Soviets , but many generals and local Azeri 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 the leading Azeri 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 , taking Shusha , Khankendi , and other important cities . By the end of April the Armenian forces were in control of most of western Azerbaijan including all of Karabakh with the surrounding areas . Other areas captured included all of Nakhchivan and much of Kazakh - Shamshadin district . In the meantime , the Armenian communists attempted a coup in Armenia , but ultimately failed . Soviet takeover , May 1920 . In 1920 - 21 the only ' solution ' of this dispute could come either by military victory – as basically happened in Anatolia , Zangezur and Nakhchivan – or by the imposition from above of a new structure by an imperial power . After the British failed to impose a settlement , the imperial arbiters turned out to be the Bolsheviks , whose 11th Army conquered Karabakh in May 1920 . On 5 July 1921 the Bolsheviks ' Caucasian committee , the Kavbiuro , under the chairmanship of Stalin ruled that the mountainous part of Karabakh would be part of Azerbaijan . In July 1923 the Nagorny ( or Mountainous ) Karabakh Autonomous Region ( NKAO ) was created within Azerbaijan , with borders that gave it an overwhelming Armenian population of 94 per cent of the total inhabitants . End of hostilities , September – November 1920 . In late November , there was yet another Soviet - backed communist uprising in Armenia . On November 28 , 1920 blaming Armenia for the invasions of Sharur ( 20 . 11 . 1920 ) and Karabakh ( 21 . 11 . 1920 ) the 11th Red Army under the command of Anatoli Gekker , crossed the demarcation line between First Republic of Armenia and Soviet Azerbaijan . The second Soviet - Armenian war lasted only a week . Aftermath . The Armenian national liberation movement was exhausted by the 6 years of permanent wars and conflicts ; the Armenian army and population were incapable of any further active resistance . Sovietization of Armenia , December 1920 . On December 4 , 1920 , when the Red Army entered Yerevan , the government of the First Republic of Armenia Armenia effectively surrendered . On December 5 , the Armenian Revolutionary Committee ( Revkom ) made up of mostly Armenians from Azerbaijan also entered the city . Finally , on the following day , December 6 , Felix Dzerzhinsky ' s dreaded secret police , the Cheka , entered Yerevan , thus effectively ending all existence of the First Republic of Armenia . The Armenian Soviet Socialist Republic was then proclaimed , under the leadership of Gevork Atarbekyan . On February 18 of 1921 a national revolt against Bolsheviks started . General Garegin Nzhdeh , commander Garo Sasouni and the last PM of independent Armenia Simon Vratsyan took the lead of anti - bolshevik rebellion and forced out the Bolsheviks from Yerevan and other places . By April the Red Army reconquered most part of Armenia . However , Atarbekyan was dismissed and Aleksandr Miasnikyan , an Armenian high - ranking Red Army commander , replaced him . Garegin Nzhdeh left the Zangezur mountains after the sovietization of Armenia was finalized in July 1921 , leaving Azeri - populated villages cleansed of their population . Persuaded by Soviet leadership , Zangezur had already been ceded by Azerbaijan to Armenia in November 1920 as a " symbol of friendship " . Treaty of Kars , 23 October 1921 . The violence in Transcaucasia was finally settled in a friendship treaty between Turkey and the Soviet Union . The peace Treaty of Kars was signed in Kars by representatives of the Russian SFSR , Azerbaijan SSR , Armenian SSR , Georgian SSR , and Turkey . Turkey had another agreement , the " Treaty on Friendship and Brotherhood " , also called the Treaty of Moscow , signed on March 16 , 1921 with Soviet Russia . By this treaty Nakhchivan was granted the status of an autonomous region within Azerbaijan . Turkey and Russia became guarantors of Nakhichevan ' s status . Turkey agreed to return Alexandropol to Armenia and Batumi to Georgia .