Banda Aceh – At least six people, including four separatist rebels, were killed in the latest violence in the restive province of Aceh, the military said Friday.

One of the four Free Aceh Movement (GAM) rebels was a 32-year-old "police chief" for the guerillas who died in a clash in North Aceh district on Friday, said Second Lieutenant Rukun Santoso, a platoon commander involved in the clash.

Aceh has been under martial law since last May when the Indonesian military began an all-out offensive to wipe out GAM, which has been fighting since 1976 for independence for the province on the northern tip of Sumatra island.

Soldiers seized a hand gun, ammunition and a handphone from the rebel.

Residents found an unidentified male corpse with torture marks in Pidie district on Friday. Three other rebels were killed in two separate clashes in South Aceh districts over the past three days, said Captain Chandra Purnama, a local military spokesman.

He also accused the rebels of killing a 35-year-old farmer in the district on Thursday. GAM officials could not be immediately reached for confirmation.

The military says it has killed more than 1,300 rebels since the offensive began. About 2,000 guerrillas and their sympathisers have been arrested or have surrendered, it says.

Indonesian authorities recently further tightened restrictions on foreign journalists wishing to visit Aceh.

The US State Department, in a report released in February, said "unlawful killings, beatings, and torture by soldiers, police, and rebels were common" in Aceh last year.

"In many cases, the victims were not combatants but civilians," it said.