Separatist rebels in Indonesia's Aceh province celebrated the anniversary Wednesday of their 1976 declaration of independence, despite warnings from the central government and the armed forces.

"The celebration of our 26th anniversary is being held at all 17 [command areas] and dozens of other areas across Aceh," said Amri bin Abdul Wahab, a field commander of the Free Aceh Movement (GAM).

Wahab said all rebel forces were on high alert for possible army attacks. He said he hoped the government would not interfere in the ceremonies "because it could disturb plans for the signing of the peace agreement on December 9."

GAM and government representatives are due to meet in Geneva next Monday to sign a deal ending the bloody separatist war. International mediators from the Henry Dunant Centre say they are confident the signing will go ahead.

Wahab said ceremonies would only be held at isolated rebel bases and there was no reason for troops to intervene. Unlike in some previous years, civilians are not being forced to attend the ceremonies or fly the separatist flag due to concern that they might face military attack.

Two blasts followed by a volley of shots were heard on the outskirts of the provincial capital Banda Aceh around midnight on Tuesday. There was no immediate report of casualties or damage.

Despite warnings from the military, the GAM flag was flown in several places on the outskirts of the town Tuesday night.

Wahab said ceremonies would depend on conditions in each command area. "But what is certain is that all GAM troops should take part in the flying of the sacred Aceh flag," he told AFP.

Some rebels marked the anniversary early. About 400 fighters observed the occasion in a ceremony in the Tamiang area in East Aceh on Monday, witnesses said.

In North Aceh, where guerrillas are very active, the ceremony was held on Tuesday. Four hundred rebel fighters and scores of local villagers attended a ceremony in a field.

A witness said Sofyan Dawod, the GAM military spokesman and North Aceh commander, presided over the proceedings. Dawod was earlier believed to be among a group of rebels which has been under siege by the army for more than three weeks in the marshy area of Cot Trieng in North Aceh.

Dawod said the siege had many loopholes, adding he expected to lead another ceremony Wednesday at the GAM's main base at Tiro in Pidie district. He said the top rebel commander, Muzakkir Manaf, could not be present because of difficulties in travelling.

GAM has been fighting for independence since 1976. More than 10,000 people have been killed since then, some 1,200 this year alone.