Philippine soldiers battled to regain control of areas in the Muslim south, where clashes have broken out over the past several days. Nearly 50 people have been killed in the fighting.

The fighting flared Saturday morning when a group of men attacked an army detachment in Indanan district, in the remote Sulu province in the Philippines' south.

A gun battle erupted in nearby Panamao town Monday when about 300 men attacked government troops. Also, a military convoy sent as reinforcement was ambushed, killing 13 Marines.

The Philippine military says the attackers were followers of detained former Muslim rebel leader, Nur Misuari. The fighters are said to been angry about a government offensive against the Abu Sayyaf terror group, which took place in their stronghold.

Philippine military spokesman, Lieutenant Colonel Buenaventura Pascual, says Mr. Misuari's supporters may have received help from the Abu Sayyaf, which has links to the al-Qaida network.

"The armed forces are still pursuing the Abu Sayyaf and the Misuari group. But we are now in control of the towns," he said.

The military has sent more troops to the area as reinforcements.

Nur Misuari led a Muslim separatist movement in the Philippines that began in the 1970s. But in 1996 he signed a peace agreement with the national government and was later elected governor of a predominantly Muslim autonomous region in the south.

An uprising by Mr. Misuari's supporters protesting his failed re-election bid in 2001 killed more than a hundred people. Since then, Nur Misuari has been detained on rebellion charges but has not yet faced trial.

Most Filipinos are Christians, but the country's southernmost islands are home to a large Muslim community.

The Philippine army, with U.S. military aid, has been fighting the Abu Sayyaf and other local terror groups. Hundreds of U.S. and Philippine soldiers will begin their next annual military exercise later this month.