By late 1941, the island of Timor was divided politically between two colonial powers: the Portuguese in the east with a capital at Dili, and the Dutch in the west with an administrative centre at Kupang. A Portuguese enclave at Ocussi was also within the Dutch area. The Dutch defence included a force of 500 troops centred on Kupang, while the Portuguese force at Dili numbered just 150. In February, the Australian and Dutch governments had agreed that in the event Japan entered the Second World War on the Axis side, Australia would provide aircraft and troops to reinforce Dutch Timor. Portugal—under pressure from Japan—maintained its neutrality. As such, following the Japanese attack on Pearl Harbor, a small Australian force—known as Sparrow Force—arrived at Kupang on 12 December 1941. Meanwhile, two similar forces, known as Gull Force and Lark Force, were sent by the Australians to reinforce Ambon and Rabaul.