Following the landings, the Japanese dispatched a sizeable naval force from Truk, reinforcing the surface elements already at Rabaul in preparation for another attack on the Allied landing forces at Bougainville. Although several tankers and transports were interdicted by Allied aircraft on 4 November, the bulk of these reinforcements arrived safely at Rabaul. This included at least seven heavy cruisers, a light cruiser and several destroyers. These posed a significant threat to the lodgment around Cape Torokina. They arrived at a time when the US Navy's capital ships were unavailable to respond, having been called back to Pearl Harbor to prepare for the Gilbert and Marshall Islands campaign. As a result, it was decided to neutralize the threat from the air. Throughout November, Allied land-based and carrier-based aircraft launched a series of bombing raids against Rabaul. The main blow fell on 5 November, when aircraft from two US aircraft carriers,"Saratoga" and "Princeton", heavily damaged four heavy cruisers. The damaged cruisers had to withdraw to Truk. This ended the threat posed to the Allied forces around Cape Torokina by the Japanese surface fleet.