Indonesian troops have killed nine more separatist rebels in Aceh province, the military said.

Four Free Aceh Movement (GAM) rebels were killed in a firefight at Teupin Tinggi in South Aceh on Monday night, said military spokesman Ahmad Yani Basuki. Troops seized three Kalashnikov rifles and one M-16. Five other guerrillas were killed in separate clashes on Monday, Basuki said.

The military says more than 900 guerrillas and 67 police or soldiers have been killed since the government imposed martial law in Aceh and launched a huge offensive on May 19 to wipe out GAM. It says more than 1,800 rebels have been arrested or have surrendered but top rebel leaders are still at large.

The military also says some 300 civilians have also been killed, but does not say by whom.

Last Thursday the government extended the military emergency for six months despite protests from right groups and concern expressed by the European Union, the United States and Japan.

GAM has been fighting for a free Aceh, a resource-rich province at the northernmost tip of Sumatra island, since 1976.