Jakarta – Pro-independence rebels in the former Portuguese colony of East Timor have killed three Indonesian soldiers, military sources said on Thursday.

The soldiers were killed in an attack in Liquisa district, west of the territory's capital Dili, on Wednesday morning, one source said.

Further information on the clash was not immediately available.

"Indeed, it's true, but for further information you will have to speak to military district's chief-of-staff," an officer in the information section of the East Timor military region told Reuters by telephone.

Residents in Dili said they were aware of the incident but it had not been reported in the local newspaper on Thursday which is subject to strict military control and censorship.

Indonesia invaded East Timor in 1975 and is still battling a small group of around 200 guerrillas opposed to its rule in the territory.

Indonesia annexed East Timor in 1976 although the act has still not been recognised by the United Nations, which regards former colonial ruler Portugal as being the administering power.

Since the eve of Indonesian elections on May 25, at least 41 people have been killed, including 16 policemen and one soldier in a single ambush, in an upsurge of violence in East Timor.