 In the build-up to, and aftermath of, the 1926-27 Nationalist Revolution, the force also struggled to contain a wave of armed robberies and politically motivated kidnappings.Throughout the 1930s it faced challenges from the Nationalist Government and the police force of the (Nationalist Chinese) City Government of Shanghai, particularly over rights to operate outside the historical bounds of the Concession and in cases of extraterritoriality.Between the Japanese occupation of China in August 1937 and the attack on Pearl Harbor on 8 December 1941, the International Settlement became the only neutral area in east China.