93rd Division. Kengtung, the main objective, was captured on 27 May. Renewed offensives in June and November saw the Chinese retreat into Yunnan. The area containing the Shan States and Kayah State was annexed by Thailand in 1942. They would be ceded back to Burma in 1945. The Seri Thai (Free Thai Movement) was an underground resistance movement against Japan founded by Seni Pramoj, the Thai ambassador in Washington. Led from within Thailand from the office of the regent Pridi, it operated freely, often with support from members of the royal family such as Prince Chula Chakrabongse, and members of the government. As Japan neared defeat and the underground anti-Japanese resistance Seri Thai steadily grew in strength, the National Assembly forced out Phibun. His six-year reign as the military commander-in-chief was at an end. His resignation was partly forced by his two grandiose plans gone awry. One was to relocate the capital from Bangkok to a remote site in the jungle near Phetchabun in north-central Thailand. The other was to build a "Buddhist city" near Saraburi. Announced at a time of severe economic difficulty, these ideas turned many government officers against him. At war's end, Phibun was put on trial at Allied insistence on charges of having committed war crimes, mainly that of collaborating with the Axis powers. However, he was acquitted amid intense public pressure. Public opinion was still favourable to Phibun, as he was thought to have done his best to protect Thai interests, specifically using alliance with Japan to support the expansion of Thai territory in Malaya and Burma.<ref>Aldrich, Richard J. The Key to the South: Britain, the United States, and Thailand during the Approach of the Pacific War, 1929–1942. Oxford University Press, 1993. </em></ref> Cold War period Allied occupation of Thailand (1946) After Japan's defeat in 1945, British, Indian troops, and US observers landed in September, and during their brief occupation of parts of the country disarmed the Japanese troops. After repatriating them, the British left in March 1946. US support for Thailand blunted Allied demands, although the British demanded reparations in the form of rice sent to Malaya, and the French the return of territories lost in the Franco-Thai War. In exchange for supporting Thailand's admission to the United Nations, the Soviet Union demanded the repeal of the anti-communist legislation. Former British POWs erected a monument expressing gratitude to the citizens of Ubon Ratchathani for