Jakarta - Seven off-duty soldiers in western Indonesia's troubled Aceh province were tortured and killed in an ambush which the military said Wednesday was orchestrated by separatists.

Armed Forces chief Wiranto called Tuesday's ambush "public brutality" and said "the same old groups who want Aceh's independence" were behind the killings. "The leaders were the ones mobilizing the masses who did not have any clue whatsoever," Wiranto said.

The military information office said about 200 people in the Lhok Nibong village in Simpang Lim district intercepted a vehicle carrying the soldiers early Tuesday. Several of the troops, who were heading towards the North Sumatra provincial capital of Medan, managed to escape and reported the attack. They said the mob, armed with sickles and knives, tortured and killed seven of their colleagues.

About 200 troops were sent in to hunt down the killers. "The perpetrators have been arrested. Twenty five of them were captured and are now under investigation," Wiranto said.

"This is public brutality that has violated the human rights of ABRI (armed forces) members," he said, adding that the National Commission on Human Rights must look into the case. The bodies of the seven killed soldiers have not been recovered.

The separatist rebel Free Aceh movement has been fighting for an independent Islamic state in Aceh since the mid-1970s. A resurgence of rebel activity in Aceh in the late 1980s prompted the military to declare the region a military operational area in which troops from outside the province were deployed to quash the rebel movement.

After the military operational status was lifted earlier this year several fact-finding teams visited the province, exhumed remains of alleged victims of the military from mass graves and alleged serious human rights violations and abuse by the military there over the past ten years.