Abu Sulaiman, one of the top five leaders of the Abu Sayyaf militant group and who is believed to have links with al-Qaeda, was killed in a gunbattle on Tuesday on the island of Jolo, military chief Gen. Hermogenes Esperon told reporters.

"We are confident that with the death of Sulaiman, who is actually the number one planner, most of the activities of the Abu Sayyaf will continue to go down," Esperon said.

Late last month, the military said Abu Sayyaf chief Khaddafy Janjalani might have been killed in September and sent tissue from a decomposing body found on Jolo for forensic tests.

"The DNA tests results are not yet with us," Esperon said. "We are told they should be coming in within the week.

If both have been killed, it will be a significant success for the Philippines. The Abu Sayyaf has only 400 or so members, most of them trapped on Jolo island, but it has been held responsible for a series of attacks, kidnapping and piracy in recent years.