The II Corps continued the Bougainville Campaign after it replaced the US Army's XIV Corps between October and December 1944. The corps consisted of the 3rd Division, 11th Brigade and Fiji Infantry Regiment on Bougainville and the 23rd Brigade which garrisoned neighbouring islands and was supported by RAAF, RNZAF and USMC air units. While the XIV Corps had maintained a defensive posture, the Australians conducted offensive operations aimed at destroying the Japanese force on Bougainville. As the Japanese were split into several enclaves the II Corps fought geographically separated campaigns in the north, centre and southern portions of the island. The main focus was against the Japanese base at Buin in the south, and the offensives in the north and centre of the island were largely suspended from May 1945. While Australian operations on Bougainville continued until the end of the war, large Japanese forces remained at Buin and in the north of the island.