Humanitarian workers urged the Philippine military and Moro rebels on Monday to avoid civilian areas amid ongoing deadly clashes in the south.

The International Committee of the Red Cross (ICRC) head of delegation Felipe Donoso said it had pointed out to both sides international conventions on war, including protecting civilians.

"We always tell them, don't do anything to hamper the security of the civilians," Donoso said. "This is the bottom-line (and is) non-negotiable."

He said the Army had been asked not to use public schools as temporary camps, while the Moro Islamic Liberation Front (MILF) should also avoid mingling with civilians.

President Gloria Arroyo has effectively suspended peace talks with the MILF after two factions of the 12,000-strong group staged a series of attacks across Mindanao in August, leaving over 60 civilians dead.

The MILF rebels torched houses and looted businesses as they fled and splintered into smaller groups.

Arroyo then poured more troops into Mindanao and soldiers have in several instances engaged MILF rebels near villages where they claim the guerrillas were taking refuge.

More than half a million people have been affected by the fighting.

Early this month, military airstrikes left a pregnant woman and five children dead near Datu Piang, a mostly Muslim town and an area known to be heavily populated by the MILF and their families and supporters.

The deaths caused public uproar, but pilots who carried out the offensive have been cleared of any wrongdoing, with the military brass saying those killed were unintended casualties of war.

Donoso said the ICRC meanwhile had received assurances from donors they would be able to fill a funding gap of 4.5 million dollars to keep relief operations in Mindanao ongoing for the year.

The budget extension appeal was issued two weeks ago after the ICRC said its whole year funding for the Philippines has nearly been depleted.

There remains a "tense situation" in Mindanao amid reports that large-scale fighting could resume once the Muslim holy month of Ramadan ends this week, he said.