Troops are clearing the rebels' compound

But one of four stragglers captured by angry civilians was hacked to death, a village official said on local radio.

The clashes came a day after more than 200 rebels were allowed to leave Zamboanga with their weapons after they freed more than 100 hostages they had been holding since Tuesday.

Southern military commander Lieutenant General Roy Cimatu said the new fighting involved about 30 members of the Muslim separatist Moro National Liberation Front (MNLF).

The rebels are loyal to the outgoing regional governor, Nur Misuari, who led an armed uprising last week, breaking a five-year peace agreement with the central government.

Deal over weapons

General Cimatu said no soldiers had been injured and he knew of no guerrilla casualties, although six had been captured.

Reports said at least 25 guerrillas, five soldiers and one civilian were killed in fighting on Tuesday.

Rigoberto Tiglao, a spokesman for President Gloria Arroyo, said the MNLF fighters had agreed to surrender their weapons to officials in the Autonomous Region Muslim Mindanao (ARMM), which administers five largely Muslim provinces in the south.

Tuesday's battle apparently began when the military tried to force the rebels, who normally act as armed guards at the office complex, to leave the area without their weapons.

A fierce gun battle ensued during which air force planes bombed the base.

The MNLF launched a long, secessionist war in the southern Philippines in the 1970s. In 1996, their then leader Mr Misuari signed a peace agreement, which set up the autonomous region with himself as governor.

But earlier this year, after performing poorly in office, the MNLF dropped Mr Misuari as their leader.

Allegations of incompetence and corruption also led the Philippines Government to back alternative candidates within the MNLF.

Mr Misuari took up arms again last week in what the Philippines authorities said was an attempt to postpone the election for his successor as ARMM governor.

Election result due

The election did go ahead and the result will be known later this week.

After the failure of his uprising, Mr Misuari fled to Malaysia, where he was arrested on Saturday. Malaysian authorities have said they are ready to deport him when the government of the Philippines was ready to receive him.

President Arroyo has said foreign countries should not grant politicial asylum to Mr Misuari but Philippines officials say they would prefer him to be kept in Malaysia for now.

They have spoken of fears that he could become a rallying point for disaffected Muslims in the Philippines.

The BBC's John McLean in Manila says the MNLF is sticking to the peace agreement, and Mr Misuari commands the loyalty of only a small faction.

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