The organisation is calling on the Indonesian authorities to exercise restraint and respect human rights in policing the rally, which is being held to mark the first anniversary of a pro-referendum demonstration by some one million people in November 1999.

Police and military are reported to have set up barricades on roads throughout Aceh to prevent people from attending the rally. Many thousands of people are said to be attempting to travel to Banda Aceh for this year's event.

There are already reports that members of the security forces have opened fire on people travelling to Banda Aceh for the rally, and that several people have been killed. Yesterday, people arriving in Banda Aceh by boat were forced to turn back after shots were fired into the air.

'The government must, as a matter of urgency, issue orders to the security forces to respect international human rights principles and not use force or firearms against unarmed, peaceful demonstrators,' said Amnesty International.

The rally's organisers have stated that they intend the demonstration to be peaceful. However, there are fears that the event may be exploited by the armed opposition group, Free Aceh Merdeka (GAM) as a show of force.

'The level of tension in Aceh is likely to be extremely high over the next few days and it is incumbent on GAM to ensure that their actions do not lead to civilian casualties,' the organisation said.