MANILA (1:43 p.m.) — Philippine marines killed six al-Qaida-linked militants early Sunday in an assault on a rebel encampment on a southern island and were investigating whether one of the dead was a top insurgent leader, a senior military commander said.

A marine special operations platoon raided an Abu Sayyaf camp outside Maimbung township on Jolo island following intelligence reports that two wanted militant leaders, Umbra Jumdail and Albader Parad, were there, said Lt. Gen. Benjamin Dolorfino, head of the military's Western Mindanao Command.

One marine was killed and three others were wounded in the clash, Philippine marines spokesman Lt. Col. Edgard Arevalo said.

Officials were trying to verify an initial report that one of the Abu Sayyaf commanders was among those killed, Dolorfino said. The operation was based on a "very strong intelligence report" that the two militant commanders were at the camp, he said.

The recovery of the slain militants and their weapons indicated the Abu Sayyaf gunmen were caught by surprise and could have suffered more casualties since it was unusual for them to leave the bodies of dead comrades behind, Dolorfino said.

He said the 30-man marine platoon was backed by other troops deployed to block the escape of the militants from their encampment on Jolo, where the militants have operated for years despite a US-backed military campaign against them.

The Abu Sayyaf, which has about 400 fighters, has been blamed for numerous bombings, beheadings and kidnappings of Filipinos and foreigners, including Americans. It is believed to have received funds from al-Qaida and is on a US list of terrorist organizations.

The US government has offered a $100,000 reward for Jumdail, also known as Dr. Abu, and $15,000 for Parad.

Parad is accused of the abduction of three international Red Cross workers on Jolo early last year. The three — a Filipino, a Swiss and an Italian — were eventually freed by the militants. (AP)