The subsequent outbreak of World War I and civil war in China meant that the Chinese factions only controlled part of Tibet. The government of the 13th Dalai Lama controlled Ü-Tsang (Dbus-gtsang) and western Kham, roughly coincident with the borders of the Tibet Autonomous Region today. Eastern Kham, separated from it by the Yangtze River, was under the control of Chinese warlord Liu Wenhui. The situation in Amdo (Qinghai) was more complicated, with the Xining area controlled by warlord Ma Bufang (of Hui ethnicity), who constantly strove to exert control over the rest of Amdo (Qinghai).