Human rights activists and local people have accused troops of massacring civilians; but a military spokesman said their action was against separatist rebels.

The discovery of the graves came as President Habibie sent a team of government officials and human rights campaigners to investigate the upsurge of violence in the province since the beginning of May.

The bodies were found in at least three mass graves near the remote village of Beuteung Ateuh, 150 km (90 miles) south-east of the regional capital Lhokseumawe.

'Killed in cold blood'

The villagers said that last Friday residents were told by the troops to gather in a field near a school for an identity check, but opened fire and massacred them in cold blood.

Jakarta Correspondent Jonathan Head: "A seemingly unstoppable cycle of violence in Aceh"

"They ... forced them to stand in rows and then executed them," said one eyewitness who escaped the alleged mass killing.

Among the corpses found in the largest grave was that of Tengku Bantaqiah, a former political prisoner who ran the school.

Lawyers and human rights activists condemned the killings as another indication of Indonesia's "savage" rule over the province.

Attack on 'armed guerrillas'

But Lieutenant Colonel Widagdo, military district commander in West Aceh, denied the massacre report.

He reiterated that 31 armed guerrillas were killed in a counter-insurgency sweep late last Friday. He said there were no other casualties in the operation.

The military has intensified a crackdown in the oil-rich province against guerrillas who want to establish an independent Muslim state. The death toll in the province this year has approached 300.

Violence in Aceh has spiralled since early May, when troops shot dead 41 civilians amid a campaign for a referendum on self-determination in Aceh.

Hundreds of buildings, including schools, have been torched and nearly 100,000 people have fled their villages fearing violence.

Megawati's promise

The frontrunner for the separate November presidential election, Megawati Sukarnoputri said on Thursday that she would do everything in her power to end the violence sweeping the vast archipelago, especially in Aceh.

Megawati: "No more blood"

"When your female leader leads this country, I will not allow a single drop of the people's blood to touch your soil...," she said in her first public speech for two months. As she spoke, she broke down sobbing and struggled to compose herself before continuing.

"I will give you my love, I will give you the yield of your Arun (gas field) so that the people can enjoy the beauty of your homeland."

Communal clashes have claimed many lives across the Indonesian archipelago in recent weeks.