Responsibility for the seizure of western New Britain was given to Lieutenant General Walter Krueger's Alamo Force. For the Cape Gloucester operation, US planners assigned the 1st Marine Division (Major General William H. Rupertus) which had previously fought on Guadalcanal. The operation would be the 1st Marine Division's second landing of the war. Initial planning had envisaged an airborne landing from the 503rd Parachute Infantry near the airfields in conjunction with a two-pronged seaborne landing either side of the cape, with two battalions of the 7th Marine Regiment advancing on the airfields from the beaches north of Borgen Bay, while another blocked ingress and egress routes along the opposite coast around Tauali. However, the airborne landing was later removed from the plan due to concerns about overcrowding of staging airfields and possible delays due to weather. To compensate, the size of the seaborne assault forces was increased. The main force assigned to the assault was drawn from the 7th Marine Regiment (Colonel Julian N. Frisbie) reinforced by the 1st Marine Regiment (Colonel William J. Whaling). In addition, the 5th Marine Regiment (Colonel John T. Selden) formed the reserve. Artillery was provided by the 11th Marines (Colonel Robert H. Pepper and later Colonel William H. Harrison). These troops were organized into three combat teams, designated 'A' to 'C': the 5th Marines formed Combat Team 'A'; the 1st Marines formed Combat Team 'B' and the 7th Marines were Combat Team 'C'.