Rebellion soon spread from the East of Xinjiang throughout the whole province and by February, 1933, when Urumqi was laid siege by joint Uyghur and Hui troops, the Provincial Government controlled no more than 10% of Xinjiang's territory. On April 12, 1933, General Sheng Shicai came to power in Xinjiang after former Governor Jin Shuren was toppled off in March by the mutinied Russian Cossack troops ( retreated to Northern Xinjiang in 1921 after losing civil war in Russia), who previously were mobilized by Jin Shuren into Provincial Army in late 1931 in desperate attempt to quell Rebellion. Sheng Shicai gained support from USSR after confirming all secret agreements that previous Governor concluded with the Soviet Union and in June 1933 he made an alliance with Hoja Niyaz against Ma Chung-ying.