However, the real beneficiaries of the conflict were the Japanese, who were able to expand their influence in both Thailand and Indochina. The Japanese wanted to use Thailand and Indochina as their military bases to invade British Burma and British Malaya later. The Japanese won from Phibun a secret verbal promise to support them in an attack on Malaya and Burma. Phibun did not keep his word. Relations between Japan and Thailand were subsequently stressed, as a disappointed Phibun switched to courting the British and Americans to ward off what he saw as an imminent Japanese invasion. However, on 8 December 1941, the Japanese invaded Thailand at the same time as the Japanese invasion of Malaya. It was immediately before the attack on Pearl Harbor because of the International Date Line. Pearl Harbor was attacked one-and-a-half hours after Malaya and Thailand were. Fighting between Japanese and Thai forces lasted only five hours before a ceasefire was agreed. Thailand would be allied with Japan until 1945. After the war, in October 1946, northwestern Cambodia and the two Lao enclaves on the Thai side of the Mekong River were returned to French sovereignty when the French provisional government threatened to veto Thailand's membership in the United Nations. The French army suffered a total of 321 casualties, of whom 15 were officers. The total number of missing after 28 January was 178 (six officers, 14 non-commissioned officers and 158 enlisted men). The Thais had captured 222 men (17 North Africans, 80 Frenchmen, and 125 Indochinese). The Thai army suffered 54 men killed in action and 307 wounded. 41 sailors and marines of the Thai navy were killed, and 67 wounded. At the Battle of Ko Chang, 36 men were killed, of whom 20 belonged to HTMS "Thonburi", 14 to HTMS "Songkhla", and two to HTMS "Chonburi". The Thai air force lost 13 men. The number of Thai military personnel captured by the French was just 21. About 30 percent of the French aircraft were rendered unserviceable by the end of the war, some as a result of minor damage sustained in air raids that remained unrepaired. The Armée de l'Air admitted the loss of one Farman F221 and two Morane M.S.406s destroyed on the ground, but its losses were really greater. In its first experience of combat, the Royal Thai Air Force claimed to have shot down five French aircraft and destroyed 17 on the ground, against the loss of three of its own in the air and another five to 10 destroyed in French air raids on Thai airfields.