invasion force the Japanese garrison on Tarakan and Borneo was subjected to intensive air and naval attacks from 12 April to 29 April. The RAAF and USAAF also mounted air attacks against Japanese bases in China, French Indochina and the NEI to suppress Japanese air units throughout the region. These attacks destroyed all Japanese aircraft in the Tarakan area. The aerial bombing of Tarakan increased in intensity five days before the landing. These attacks were focused on the areas adjoining the planned landing beaches at Lingkas and sought to neutralise the Japanese defences in these areas. The oil storage tanks at Lingkas were a key objective as it was feared that the oil in these tanks could be ignited and used against Allied troops. These bombardments forced much of Tarakan's civilian population to flee inland. At least 100 civilians were killed or wounded. The Tarakan attack force was assembled at Morotai during March and April 1945. The 26th Brigade Group was transported from Australia to Morotai by United States Army transports and arrived in mid-April and began to prepare their equipment for an amphibious landing. Due to a shortage of shipping all units were ordered to leave non-essential vehicles at Morotai when they began to embark onto assault transports on 20 April. The commander of the 1st Tactical Air Force attempted to resist this order, but was over-ridden by his superior officer Air Vice Marshal William Bostock. Most units were embarked by 22 April and the assault troops practiced landing operations for several days. A small convoy of ships carrying a force ordered to capture Sadau Island off the coast of Tarakan left Morotai on 26 April, and the main invasion convoy of 150 ships sailed the next day. Due to the need to clear both the large number of naval mines which had been laid around Tarakan and the extensive beach obstacles at Lingkas, the Allies did not attempt a surprise landing. A group of United States Navy minesweepers and destroyers arrived off Tarakan on 27 April and began clearing mines, most of which had been originally laid by Allied aircraft. This operation was completed by 1 May at a cost of two small minesweepers damaged. USN PT boats also arrived off Tarakan on 28 April and illuminated and strafed the invasion beaches at night to prevent the Japanese from repairing their beach defences. The PT boats also attacked