| East Timorese civil war | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| |||||||||
| Belligerents | |||||||||
 Timorese Democratic Union (UDT) |
 Revolutionary Front for an Independent East Timor (Fretilin) | ||||||||
| Commanders and leaders | |||||||||
|
João Viegas Carrascalão |
Francisco Xavier do Amaral | ||||||||
| Units involved | |||||||||
| Movement for the Unity and Independence of the Timorese People | Armed Forces for the National Liberation of East Timor | ||||||||
| Casualties and losses | |||||||||
| 1,500–3,000 | |||||||||
In August 1975, a civil war broke out between two opposing political parties in Portuguese Timor: the conservative Timorese Democratic Union (UDT) and the left-leaning Revolutionary Front for an Independent East Timor (Fretilin). The war took place within the context of decolonisation, as the post–Carnation Revolution Portuguese government sought to give independence to much of the Portuguese Empire. UDT and Fretilin were formed in May 1974, following the legalisation of political parties in Portugal. UDT initially advocated for continuing ties to Portugal, before shifting to promoting a gradual independence process that maintained existing institutions. Fretilin sought independence with a new political system that would address a widespread lack of development in the territory. Also formed during this time was the Timorese Popular Democratic Association (Apodeti), which advocated for an Indonesian annexation of the territory, although Apodeti gained far less popular support than the other two major parties.
Discussions about the future of East Timor took place within the context of the views of neighbouring Indonesia. The Indonesian government saw an independent East Timor with a potentially communist government as a security risk. This view found receptive ears among Western governments affected by the recent loss of the Vietnam War. As the left-leaning Fretilin established itself as a popular political force, Indonesia applied pressure on Portugal and the other East Timorese political parties to find a pathway excluding Fretilin. The UDT and Fretilin found common ground and made a joint proposal to Portugal in January 1975 on a path to independence. However, deep mistrust between the parties, especially between their more radical wings, eventually led to a breakdown of relations.
Tensions between UDT and Fretilin came to a head on 11 August 1975 when UDT forces took control of key points in the cities of Dili and Baucau. Although this was successful and caused Fretilin leaders to flee, Fretilin began a counter-attack on 20 August. After retaking the two major cities, Fretilin continued its military campaign, and took control of most of the country by early September. The conflict exacerbated existing local tensions throughout the territory, and between 1,500 and 3,000 people are thought to have been killed during this period by both forces and in other acts of violence. The remaining Portuguese authorities retreated to the island of Atauro, while UDT leaders fled to Indonesia, leaving Fretilin as the effective government. Fretilin called for the return of Portuguese authorities and a resumption of decolonisation discussions, while setting up a caretaker government to manage the territory in the meantime.
UDT leaders who had retreated to Indonesia began to advocate for Indonesian annexation, and Indonesia provided them with training and other military support. Indonesian special forces worked with the UDT to carry out attacks near the border, making limited gains in October. On 20 November a new offensive was launched with more significant Indonesian support. Following the refusal of Portuguese authorities to return, and losing ground to the combined UDT–Indonesian offensive, Fretilin hastily declared the independent Democratic Republic of East Timor. Indonesia responded by publicly coming out in favour of annexation, launching a full-scale invasion on 7 December, and setting up the Provisional Government of East Timor led by its allied political parties. Indonesia formally annexed East Timor on 17 July 1976.