 Complete the following phrase:  In October 1919, the Anhui warlord Xu Shuzheng led the military occupation of Mongolia and Tuva, backed by the Empire of Japan. In February 1921, the Chinese occupation forces were ousted by the White general Roman von Ungern-Sternberg, who restored Bogd Khan to the throne and led pogroms against Mongolian leftists and Jews. Buryat anarchists took up the 