Philippine troops found four bodies including the mutilated corpses of two soldiers after a breakaway Muslim rebel group launched co-ordinated raids in the south, the army said Tuesday.
The discoveries raised the death toll to seven a day after the Bangsamoro Islamic Freedom Fighters simultaneously attacked 11 towns on Mindanao island, said the soldiers' commander Lieutenant-Colonel Kit Teofilo.
"The face of one soldier was mangled (and he) was shot in the head. The other had torture marks all over his body including hack wounds. It was a horrible crime committed by heartless individuals," Teofilo said.
The corpses of two more male victims were recovered at a roadside, also suspected to have been killed by the raiders, the battalion commander said in a statement. Another soldier was still missing, he added.
The military had earlier reported that a civilian and two of the raiders were killed in the skirmishes.
The rebels used chainsaws to bring down electricity pylons before dawn on Monday, plunging several towns into darkness, and then opened fire on army detachments, police and the military said.
Teofilo said most of the fighting had died down by early Tuesday, but army units in the area were still drawing sniper fire as they searched for the missing soldier near the towns of Datu Unsay and Datu Saudi Ampatuan.
The government says the attacks were apparently meant to derail negotiations with the larger, more mainstream Moro Islamic Liberation Front (MILF).
The breakaway rebels are headed by Ameril Umbrakato, a hardline Saudi Arabian-educated guerrilla who split from the 12,000-strong MILF after it dropped its bid for full independence to negotiate for an autonomous region.
Umbrakato has boasted of having about 5,000 armed fighters, though military officials believe he only has a few hundred under his command.
The government has said it hopes to sign a peace deal with the MILF by the end of the year, but has asked the MILF leadership to help contain the forces of Umbrakato, who opposes peace talks.
The Mindanao insurgency began in the early 1970s and the fighting has killed some 150,000 people, miring large parts of the south in deep poverty.