Indonesia has sent seven navy frogmen to a small reef that neighbouring Malaysia has also claimed as its territory, a report said yesterday.

The elite troops were dropped on the Karang Unarang reef in the Sulawesi Sea from an aircraft, navy spokesman Lieutenant Colonel Guntur Wahyudi told the state-run Antara news agency without giving a date.

Wahyudi said the frogmen were deployed on the reef to assist with work to construct a lighthouse there. The area is claimed by both Indonesia and Malaysia.

Last month, Indonesian workers working on the lighthouse complained that Malaysian troops who landed on the reef had roughed them up.

The incident further fueled the tension between the two countries that had erupted after Kuala Lumpur awarded an offshore oil concession contract to an international oil company in the disputed area.

Although the leaders of the two countries have already agreed to settle border disagreements through dialogue, anger against Malaysia has remained strong among some Indonesians.

Anti-Malaysian groupings in several Indonesian towns and cities have opened registration for volunteers in case war broke out with Malaysia over the issue.

Gus Dur: Remain calm

Meanwhile, former Indonesian president Abdurrahman "Gus Dur" Wahid on Sunday called on his countrymen to remain calm and not resort to violence despite their anger against Malaysia.

"Most important is, how to settle the issue through a dialogue. Don't ever launch any attack," Wahid told Muslims during a major gathering at a mosque in Surabaya, East Java, the state Antara news agency reported.

Indonesia declared war against Malaysia after tensions about the future of Borneo island in 1963 after the British relinquished control. The conflict ended three years later.

Malaysia and Indonesia have also already locked horns over the territory in the area before. A dispute over the ownership of two islands ended in December 2002 with an International Court of Justice ruling that they belong to Malaysia.

The agreement for dialogue came after both countries beefed up their military effective in the area to support their claim.

Warships from both countries have come into close contact in the Sulawesi Sea east of Borneo several times.