The German government was accused of being behind Zhang Xun's monarchist coup in China to prevent Duan Qirui's pro-war faction from supporting the Allies. After the coup failed in July 1917, Duan used the incident as a pretext for declaring war on Germany. The German and Austro-Hungarian concessions in Tientsin and Hankow were occupied and their nationals detained. China also supplied civilian laborers to the Allies for mainly non-combat and auxiliary roles on the Western Front.