Army troops backed by artillery and armored vehicles clashed with Muslim separatist rebels in the southern Philippines, leaving 20 guerrillas and seven soldiers dead, the military said on Saturday. Regional military spokesman Lt. Col. Jonathan Ponce said troops from the army's 601st Brigrade had been checking reports that rebels under a rogue commander of the separatist Moro Islamic Liberation Front were massing in a hamlet in the village of Bialong when fighting erupted with about 80 guerrillas before dawn on Friday and dragged on for at least eight hours. It was one of the fiercest clashes with the rebels under Commander Umbra Kato this year, Lt. Col. Ponce said, adding five other soldiers were wounded in the fighting outside Mamasapano township in Maguindanao province. Troops have been ordered to hunt down Kato and two other rogue rebel commanders who led a bloody rampage that killed dozens of civilians in several communities in Lanao del Norte province after a preliminary peace deal was scrapped last August, Lt. Col. Ponce said. He said the rebels were believed to be planning to launch attacks again against civilian communities. Lt. Col. Ponce said the military believes the rebels suffered a larger number of casualties, mainly from artillery shelling, as advancing troops discovered mangled remains. Troops were continuing to pursue the fleeing rebels, but no fresh clashes were immediately reported on Saturday, he said. Peace negotiations between the government and the rebels fell apart in August when the Supreme Court blocked the signing of a preliminary accord that would have expanded a Muslim autonomous region in the southern Mindanao region, where a Muslim separatist war has raged for decades. The accord was challenged by Christian politicians who feared they would lose land, power and clout to minority Muslims. As a result, a bloody rampage was unleashed in predominantly Christian communities, provoking a major military offensive that displaced more than half a million people. The clashes have eased to sporadic fighting, but tens of thousands of villagers have refused to go home, officials said. The government has reconstituted its negotiating panel, but no schedule has been set for Malaysian-broked talked to resume.