The island of Ambon, in the Dutch East Indies, was perceived to be under threat from Japan because of its potential as a major air base. However, by mid-December 1941, only two flights of RAAF light bombers were deployed there, along with assorted obsolete US Navy and Royal Netherlands Navy aircraft. The 8th Division's 1,100-strong Gull Force, commanded by Lieutenant Colonel Leonard Roach, commanding officer of the 2/21st Battalion, arrived on 17 December. In addition to the 2/21st Battalion, it included 8th Division artillery and support units. The existing Royal Netherlands East Indies Army garrison, commanded by Lieutenant Colonel Joseph Kapitz, consisted of 2,800 Indonesian colonial troops, with Dutch officers. Kapitz was appointed Allied commander on Ambon. Roach had visited the island before Gull Force's deployment and requested that more artillery and machine gun units be sent from Australia. Roach complained about the lack of response to his suggestions, and he was replaced by Lieutenant Colonel John Scott on 13 January 1942.