Philippine troops bombarded the Abu Sayyaf camp with artillery and mortar fire near Jolo island's Indanan township early on Wednesday, killing at least one militant and wounding rebel commander Isnilon Hapilon, regional military spokesman Major Eugene Batara said.

At least one Filipino soldier was wounded in ensuing clashes, he said, adding the military was trying to verify other reports of rebel casualties.

Marine Brig Gen Juancho Sabban, commander of military forces on the island, said that he ordered the attack after intelligence reports indicated an 'unusual convergence' of Abu Sayyaf commanders and a top Indonesian terrorism suspect, Umar Patek, who could be plotting a bomb attack.

About 100 to 150 militants were at the encampment, which had about 30 huts, when it was attacked. Several explosives in a bomb-making facility in the encampment were destroyed by artillery and mortar fire, Brig Gen Sabban said.

'The important thing is we managed to dismantle the bomb-making facility,' Brig Gen Sabban said by telephone from Jolo.

'They were up to something big.' Troops were pursuing the militants, who fled in small groups, he said.

Hapilon was wounded in the hand during the fighting. There have been reports that his son, an Abu Sayyaf member identified as Tabari, may have been killed, but the military has not been able to confirm that, Batara said.

Jolo Governor Sakur Tan met mayors of townships near the scene of Wednesday's clash to be ready to help jittery villagers, who might abandon their homes due to the fighting.

Washington has offered a US$5 million (S$6.79 million) reward for Hapilon, who has been linked to the abduction of 17 Filipinos and three Americans in May 2001.

Abu Sayyaf, which is estimated to have 380 fighters - down from 1,000 eight years ago - is believed to have launched its last major attack in February 2005 with simultaneous bombings in Manila and two southern cities that killed eight people and wounded more than 100.

Despite problems, the guerrillas have continued to plot attacks, including against American soldiers who have been providing counterterrorism training to Filipino troops in the country's volatile south, police said.

Washington has blacklisted Abu Sayyaf as a terrorist organization. Philippine military and police officials say the group - which seeks a separate state for the country's Muslim minority - has received training and funds from Al-Qaeda militants in the past. -- AP