Indonesia–Malaysia confrontation party which was founded in June 1959. The Sarawak Insurgency began after the Brunei Revolt in 1962 and SCO would fight alongside the Bruneian rebels and Indonesian forces during the Indonesia–Malaysia confrontation (1963–1966). The Sarawak Communist Organisation and the Bruneian rebels supported and propagated the unification of all British Borneo territories to form an independent leftist North Kalimantan state. This idea was originally proposed by A. M. Azahari, leader of the Parti Rakyat Brunei (Brunei People's Party), who had forged links with Sukarno's nationalist movement, together with Ahmad Zaidi, in Java in the 1940s. However, the Brunei People's Party was
Brunei–Malaysia border World War II, joined Malaysia on 16 September 1963. Brunei remained a British Protectorate until 1984 when it gained independence. Brunei and Malaysia have had long standing disputes over land and maritime territories. However, due to the cultural ties between the two countries, the disputes have always been low-key and deemed too sensitive to be discussed openly. The main land dispute was over the district of Limbang which has been controlled by Sarawak since 1890, while the dispute over maritime territory involved virtually the entire deep sea section of the South China Sea claimed by Brunei which Malaysia asserted as