Indonesia–Malaysia confrontation of the action occurring in the border area between Indonesia and East Malaysia on the island of Borneo (known as Kalimantan in Indonesia). The conflict was characterised by restrained and isolated ground combat, set within tactics of low-level brinkmanship. Combat was usually conducted by company- or platoon-sized operations on either side of the border. Indonesia's campaign of infiltrations into Borneo sought to exploit the ethnic and religious diversity in Sabah and Sarawak compared to that of Malaya and Singapore, with the intent of unraveling the proposed state of Malaysia. The challenging jungle terrain of Borneo and lack of roads straddling
Geography of Malaysia districts. There are separate subdivisions for electoral districts for polling purposes. International borders between Malaysia and Indonesia, Thailand, Singapore and Brunei are defined mostly by geological features such as the Perlis River and Golok River between Malaysia and Thailand; Straits of Johor between Malaysia and Singapore; and Pagalayan Canal between Malaysia and Brunei. However, borders that extends to the seas are defined by agreements such as Straits Settlement and Johore Territorial Waters Agreement of 1927 which defines Malaysia and Singapore water borders. Malaysia's land borders are well established. The border with Thailand was established in 1909 when Siam ceded Kedah,