Philippine army troops clashed with communist guerrillas in a fierce gunbattle that killed two rebels and two children who were with the insurgents in a northwestern province, officials said Sunday.

Regional military commander Maj. Gen. Josue Gaverza Jr. said he had ordered an investigation to determine if the soldiers committed lapses that led to the deaths of the two boys, aged 7 and 10, and the wounding of their sister during Saturday's clash in a remote village in Camarines Norte province.

The three, who were believed to be children of one of the slain rebels, were hit in the crossfire, Gaverza said.

A platoon of soldiers traveled to the village in Labo town after being tipped off by residents that New People's Army guerrillas had arrived in the area in search of food and to extort money. As they approached, about 15 guerrillas opened fire from a hut and a nearby hill, sparking a brief but intense gunbattle, army Lt. Col. Epimaco Macasilang said.

After the outnumbered guerrillas withdrew, troops found the bodies of two rebels and the boys in the hut. The boys' 14-year-old sister was also found in the hut with a gunshot wound to her wrist and taken to hospital, army officials said.

Gaverza said he was saddened that the children were caught in the crossfire.

Regional army spokesman Maj. Angelo Guzman said the soldiers were unaware there were children in the hut, where some rebels were firing from and two rifles were later found. It was not immediately clear who hit the children, he said.

More than 120,000 combatants and civilians have been killed in the 43-year insurgency, one of Asia's longest. The rural-based rebellion has endured amid widespread poverty, landlessness and faulty governance in the country's poor countryside.

The Maoist rebels, estimated to have slightly more than 4,000 fighters, killed about 100 government troops and police and waged 447 attacks last year despite a steady but considerable weakening of the insurgency, the military says.