For the operation, the corps was placed directly under General Douglas MacArthur's command, rather than being assigned to the US Eighth Army. Advanced elements of I Corps headquarters subsequently moved to Morotai Island in March 1945, followed by the remainder of the headquarters the following month. From there, they directed a series of amphibious landings that were carried out by the 7th and 9th Divisions at Tarakan, North Borneo and Balikpapan through May, June and July. In all locations, the objectives were captured, albeit against stronger-than-expected resistance in some cases, with commensurately heavy casualties, after which the Australians pushed further inland, carrying out mopping up operations. On Tarakan, the airfield was captured five days after the landing, but it was badly damaged and ultimately filled no role in subsequent operations. Meanwhile, in North Borneo, after operations to secure Labuan and Brunei had proved successful, a follow up landing was made around Weston, with a subsequent advance towards Beaufort, which was captured after heavy engagement resulted in over 100 Japanese killed. By mid-July, the main resistance around Balkipapan and the coastal areas had been overcome, and the defending Japanese had withdrawn into the hills further inland.