On 8 December 1941, during the Second World War, the Japanese invaded Thailand, and crossed Pattani to invade British Malaya. The Thai government, led by Marshall Plaek Phibunsongkhram became an active ally of Japan by promising to help Thailand retake some territorial claims back from the British and the French. This included Sirat Malai, the former Malay dependencies of Kelantan, Trengganu, Kedah, and Perlis. It is arguable that this move not only gave more territory to the Thai state but on the contrary, it strengthened the old Malay ties between the Pattani region and the northern Malayan peninsula states.