徐树铮
Following the Russian Revolution of October 1917, China revived its claims to Outer Mongolia, aiming at its conversion into a common Chinese province. In late 1919, the Chinese general Xu Shuzheng occupied Urga after suspicious deaths of Mongolian patriotic nobles and forced the Bogd Khaan and the leading nobles to sign a document renouncing Mongolia's independence. Leaders of Mongolia's national independence movement, such as Magsarjav and Damdinsüren (died in the prison under brutal torture) were arrested and imprisoned. The Chinese had tightened their control of Mongolia by this time.