In September 1920, remnants of the Ottoman Army's XV Corps under the command of Kâzım Karabekir attacked the First Republic of Armenia, specifically in the Kars. Karabekir had orders from the Ankara Government to "eliminate Armenia physically and politically". One estimate places the number of Armenians massacred by the Turkish army during the invasion at 100,000—this is evident in the marked decline (−25.1%) of the population of modern-day Armenia from 961,677 in 1919 to 720,000 in 1920. The Turkish military victory was followed by the Red Army invasion of Armenia and the establishment of the Armenian Soviet Socialist Republic. The Turkish invasion and occupation had drastic humanitarian impacts to Armenia's population, triggering condemnation from German and USA officials. According to several historians, only Soviet intervention prevented the completion of the Armenian genocide.
The hostilities ended with the Treaty of Alexandropol and the effective partition of Armenia between Kemalist Turkey and the Soviet union: most of Western Armenia was transferred to Turkey and Eastern Armenia was incorporated into the Soviet Union as the Armenian Socialist Republic. This status was solidified by the annulment of the Treaty of Sevres, and the ratification of the Treaty of Moscow (March 1921) and Treaty of Kars (October 1921) between Soviet Russia and the Grand National Assembly of Turkey.
