Grave human rights abuses including the killing of children and other civilians are already being reported in Indonesia's Aceh province, Amnesty International says.

A major military offensive aimed at crushing the Free Aceh Movement (GAM) entered its second week today in the province, which has been placed under martial law.

Amnesty, in a weekend report, urged both sides to make protection of civilians a priority and said it is gravely concerned that martial law will make abuses more likely.

"There are already reports that this is the case and that civilians, including children, have been subjected to extrajudicial execution, and that many thousands of people have been forced to flee their homes..." the report said. "Amnesty International reminds the government of Indonesia that the declaration of a military emergency does not allow derogation of basic human rights..."

The London-based group said Jakarta must follow several steps "if the massive human rights violations which have characterised previous operations are not to be repeated." Amnesty welcomed statements by various officials that civilian casualties would be avoided and rights respected but urged the government to make an official public statement to this effect.

In a reference to Major General Adam Damiri, it expressed "particular concern" that a senior officer on trial in Jakarta for crimes against humanity in East Timor in 1999 has a direct role in Aceh military operations.

It also took issue with army chief General Ryamizard Ryacudu, who recently described as "heroes" seven soldiers who were convicted of murdering pro-independence leader Theys Eluay in Papua.

Amnesty said the government must "issue clear and strongly worded directives" to security forces to stick to international human rights and humanitarian law. Guilty parties must be prosecuted.

"Despite the thousands of cases of human rights violations that have been reported in [Aceh] over the years, in only three cases known to Amnesty International have investigations been completed and members of the security forces been brought to trial," it said.

Even before martial law, it said, "torture of detainees in both police and military custody was widespread as were deaths in custody and 'disappearances' of suspects." In Aceh and elsewhere in Indonesia in the past, Amnesty said, security forces have tortured or raped women and girls as a form of intimidation and as punishment for their, or their relatives', alleged involvement with opposition groups.

Since 2000, the rights group said, 13 human rights defenders are believed to have been executed in Aceh and scores of others subjected to torture, detention without charge and harassment and intimidation.

Amnesty also said there have been credible reports of unlawful killings, abductions and torture by GAM members both against members of the security forces and civilians. The rebels had also recruited child fighters, it said, calling on rebel commanders publicly to declare their opposition to rights abuses by its members.