Red Army invasion of Azerbaijan

The Red Army invasion of Azerbaijan, also known as the Sovietization or Soviet occupation of Azerbaijan, was a military campaign carried out by the 11th Army of Soviet Russia on 27 April - 11 May 1920 to install a new Soviet government in the Azerbaijan Democratic Republic, a former territory of the Russian Empire. The invasion coincided with the anti-government insurrection staged by the local Azerbaijani Bolsheviks in the capital Baku.

Background
By early 1920, Soviet Russia desperately needed oil supplies from Baku. On 17 March 1920, Vladimir Lenin sent the following telegraph to the Revolutionary Military Council on the Caucasus Front:

In January 1920, Mikhail Tukhachevsky, who arrived to Petrovsk-Port (present-day Makhachkala) along with the member of the Revolutionary Military Council, Sergo Ordjonikidze, was appointed as the commander Red Army's Caucasus district. On 21 April 1920, Tukhachevsky issued the following directive for the 11th Red Army and the Volga-Caspian military flotilla to initiative an offensive towards Baku:

Military operation
According to the Russian historian A.B. Shirokorad, the Soviet invasion of Azerbaijan was carried out using a standard Bolshevik template: a local revolutionary committee starts real or "virtual" worker riots and requests support from the Red Army. This scheme was used also decades later, during the Soviet invasions in Hungary (1956) and Czechoslovakia (1968). On 28 April 1920, the Baku Revolutionary Committee filed a formal request for help with the Soviet Russian Government. But a day before, the 11th Red Army, including the 26th, 28th and 32nd rifle divisions and 2nd mounted corps (over 30,000 soldiers), already invaded the territory of Azerbaijan.