The outbreak of WWII disrupted Commonwealth operations. Christians and Muslim officers and men of the military district in Mindanao and Sulu shifted to guerilla activities against the Japanese. A civil government called Free Sulu Government administered activities in the locality. The Japanese Occupation forces established a government in Basilan to govern both Zamboanga and Basilan. The Japanese Occupation of Basilan was rather uneventful; it barely disturbed Yakan society, except in terms of Japanese demand for food for their military.