The Chita Operations was one of the final campaigns on the Eastern Front of the Russian Civil War, in which the socialist Far Eastern Republic destroyed the White Russian holdout enclave of Chita in East Asia. Bolshevik partisans had taken over Krasnoyarsk on 24 December 1919 and Irkutsk on 5 January 1920, and, on 6 April 1920, a coalition of Bolsheviks, Mensheviks, and Left SRs formed the Far Eastern Republic as a semi-autonomous buffer state between the Russian SFSR and the White-controlled Russian Far East. The Far Eastern Republic claimed to control Kamchatka, Zabaykalsky Krai, Primorsky Krai, Sakhalin, Amur Oblast, and the Chinese Eastern Railway, but Ataman Grigory Semyonov's Whites controlled the eastern portion of Zabaykalsky Krai, forming the "Chita Holdup". The Far Eastern Republic raised an army of 10,000 troops from Red Amur partisans, leftist political prisoners, and former White Army prisoners, and, in March, these forces were transferred to Transbaikal. On 10 April, the Reds launched an offensive against the Whites of Chita, but two Red assaults were defeated by the Whites. On 15 July 1920, Japan signed a treaty with the Reds, leading to the Imperial Japanese Army's withdrawal from the region; this severely weakened the isolated Whites, and the FER's army was restructured by its new commander, Genrich Eiche. On 1 October 1920, Eiche launched an offensive against Semyonov's demoralized Whites, and, by the end of the month, Chita had fallen. The left flank of the Whites fled to Manchuria, and the defeat of the Whites led to the Japanese hastening their evacuation from Khabarovsk, putting an end to White resistance in the Far East.