According to Vernon L. Porritt and Hong-Kah Fong, Left-wing and communist cell groups had been present among Sarawak's urban Chinese communities since the 1930s and 1940s. Some of the earliest Communist groups in Sabah included the Anti-Fascist League, which later became the Races Liberation Army, and the Borneo Anti-Japanese League, which was made up of the North Borneo Anti-Japanese League and the West Borneo Anti-Japanese League. The latter was led by Wu Chan, who was deported by the Sarawak colonial government to China in 1952. Other Communist groups in Sarawak included the Overseas Chinese Youth Association, which was formed in 1946, and the Liberation League along with its youth wing, the Advanced Youth Association, which emerged during the 1950s. These organisations became the nuclei for two Communist guerrilla movements: the anti-Malaysia North Kalimantan People's Army (PARAKU) and the Sarawak People's Guerrillas (PGRS). These various Communist groups were designated by various British and other Western sources as the Clandestine Communist Organisation (CCO) or the Sarawak Communist Organisation (SCO).