Police in Indonesia's Aceh province said they were hunting civilian activists suspected of supporting separatist rebels.

"We will use the [criminal code] article on subversion, which carries up to the death sentence, against them," said Sayed Husaini, police spokesman in the province where a major military assault on the rebels is in its third week.

Activists who give support or assistance to the Free Aceh Movement (GAM) are violating the law, he said Tuesday, adding that police have records and evidence against them.

He gave no details on the size of the wanted list other than to say "they number a lot." Many are student activists from the Ar-Raniry State Institute for Religious Sciences in Banda Aceh or members of several non-governmental organisations, he said.

The spokesman cited only one individual, Kautsar bin Muhammad Yus, the son of the head of the provincial parliament. Among the NGOs he cited were the Information Center on a Referendum for Aceh, which campaigns for an independence referendum, and Society's Solidarity for the People.

Husainy said police were questioning 70 detained GAM members, including five peace negotiators who were arrested soon after the government declared martial law and launched its military operation on May 19.

Two powerful blasts at Kampung Mulia on the outskirts of Banda Aceh rocked the city late Monday but caused no casualties. Husainy said home-made bombs and grenades exploded by GAM were the cause and there had been two similar blasts on a previous evening.

Up to 40,000 police and soldiers are confronting an estimated 5,000 rebels from GAM in Indonesia's biggest military operation for a quarter-century. GAM has been fighting for an independent state since 1976 and some 10,000 people, mostly civilians, have been killed since then.

In Jakarta a foreign ministry official said Aceh's martial law administrator, Major General Endang Suwarya, has rejected requests from about 10 overseas journalists to cover the conflict there.

The official, Wahid Supriyadi, said his office normally reviews visa requests by journalists based outside Indonesia. But the authority lies with Suwarya since martial law was declared in Aceh on May 19, he said.

Suwarya was quoted Tuesday as saying he did not need "foreign observers" in the province. "We are capable of overcoming by ourselves the problem here," he said, as quoted by the Kompas daily.