Manila: Communist guerrillas killed an army officer and seized 29 assault rifles in southern Philippines in one of their most successful attacks on a military target this year, the army said on Wednesday.

About 50 New People's Army guerrillas attacked a pro-government militia patrol base late Tuesday near Banlag town in southern Bukidnon province, setting off a gunbattle that killed an army sergeant and wounded a militiaman, army spokesman Major Ernesto Torres said.

Several guerrillas were wounded during the clash and taken away by other rebels. An army platoon of about 30 soldiers was deployed to the site to secure the base and help pursue the attackers, he said.

Among the firearms taken were M-16 and M-14 rifles, which are used by snipers, he said. "This is a big debacle, definitely it will be investigated because so many firearms were taken," Torres said.

The NPA, fighting one of the world's oldest communist insurgencies, often attacks remote military and police facilities to steal weapons and ammunition.

"Our fighters caught them by complete surprise," said Cesar Renerio, an NPA spokesman in Bukidnon province.

"Several members of a paramilitary unit inside the base did not offer any resistance. At least 29 M-16 rifles were taken from the detachment."

Separately, about 30 armed guerrillas took medicine from residents in the coastal village of Buayan in southern Zamboanga Sibugay province on Wednesday, and used their village to rest and eat lunch, officials said.

They forced a Protestant pastor and about 10 other villagers to remain inside a small Bible school to prevent them from informing authorities about their presence.

"The NPA rebels gathered the villagers, students, teachers in one area apparently to prevent them from reporting their presence to the police or military," said Lt Col Susthenes Valcorza, spokesman of the military's Southern Command.

The guerrillas left Buayan in three batches without harming anyone. They took a two-way radio set from the church, said police officer Elrey Velasco, who went to Buayan to investigate.

Army troops were deployed but failed to find the guerrillas. Security was strengthened in nearby cities by the military, fearing the rebel presence in Buayan could be a tactic to divert the military's attention ahead of a major attack elsewhere, Valcorza said.

In June, President Gloria Arroyo ordered an intensified campaign to finish off the estimated 7,000-strong NPA, which has been waging a rural-based rebellion for 37 years. Her order came amid a spike in rebel attacks on military and police targets.

The rebels, who claim to operate in nearly 70 of the Philippines' 79 provinces, broke off from Norwegian-brokered peace talks two years ago to protest the government's refusal to lobby for their removal from US and European lists of terrorist groups.