Ba Maw served as the first prime minister of Burma, but he was succeeded by U Saw in 1939, who served as prime minister from 1940 until he was arrested on 19 January 1942 by the British for communicating with the Japanese. A wave of strikes and protests that started from the oilfields of central Burma in 1938 became a general strike with far-reaching consequences. In Rangoon student protesters, after successfully picketing the Secretariat, the seat of the colonial government, were charged by the British mounted police wielding batons and killing a Rangoon University student called Aung Kyaw. In Mandalay, the police shot into a crowd of protesters led by Buddhist monks killing 17 people. The movement became known as "Htaung thoun ya byei ayeidawbon" (the '1300 Revolution' named after the Burmese calendar year), and 20 December, the day the first martyr Aung Kyaw fell, commemorated by students as 'Bo Aung Kyaw Day'. Some Burmese nationalists saw the outbreak of World War II as an opportunity to extort concessions from the British in exchange for support in the war effort. Other Burmese, such as the Thakin movement, opposed Burma's participation in the war under any circumstances. Aung San co-founded the Communist Party of Burma (CPB) with other Thakins in August 1939. Marxist literature as well as tracts from the Sinn Féin movement in Ireland had been widely circulated and read among political activists. Aung San also co-founded the People's Revolutionary Party (PRP), renamed the Socialist Party after the World War II. He was also instrumental in founding the Freedom Bloc by forging an alliance of the Dobama, ABSU, politically active monks and Ba Maw's Poor Man's Party. After the Dobama organisation called for a national uprising, an arrest warrant was issued for many of the organisation's leaders including Aung San, who escaped to China. Aung San's intention was to make contact with the Chinese Communists but he was detected by the Japanese authorities who offered him support by forming a secret intelligence unit called the "Minami Kikan" headed by Colonel Suzuki with the objective of closing the Burma Road and supporting a national uprising. Aung San briefly returned to Burma to enlist twenty-nine young men who went to Japan with him to receive military training on Hainan Island, China, and they came to be known as the "Thirty Comrades". When the Japanese occupied Bangkok in December 1941, Aung San announced the formation of the Burma Independence Army (BIA) in anticipation of the Japanese invasion of Burma in 1942.