As war broke out in the Pacific Japanese forces based in Vichy French-controlled Indochina quickly overran Thailand and invaded Malaya. The loss of two British capital ships, HMS "Repulse" and HMS "Prince of Wales", off Malaya on 10 December 1941, neutralised Allied naval superiority, allowing the Japanese to perform amphibious assaults on the Malayan coast with much less resistance. Japanese forces met stiff resistance from III Corps of the Indian Army and British units in northern Malaya, but Japan's superiority in air power, tanks and infantry tactics forced the British and Indian units, who had very few tanks and remained vulnerable to isolation and encirclement, back along the west coast towards Gemas and on the east coast towards Endau.