After the start of the Second Sino-Japanese War in 1937, the Chinese merchant community engaged in a surprisingly violent boycott of Japanese goods. As relations between Japan and the United Kingdom deteriorated, Japanese expatriates in Singapore and other British territories resettled in Siam to avoid potential internment. The 1941 Japanese invasion and occupation of Thailand brought many more Japanese to the country. After the war ended, the British military authorities repatriated them all to Japan, including the civilians, unless they could prove that they had been long-term residents of the country. Repatriation efforts were held up by war crimes prosecutions. By September 1946, still about one-sixth of the Japanese who had been in Southeast Asia at the war's end remained there, including about 9,500 Japanese in Siam.