Manila, Feb 11 (IANS): Four soldiers were killed and another critically wounded after a soldier ran amok and fired at sleeping soldiers inside an army camp in northern Mindanao, south of the Philippines, on Saturday, said the Philippine military.

The alleged murderer was also shot dead, Xinhua news agency reported.

The incident happened at around 1:10 p.m. local time inside Camp Evangelista in Cagayan de Oro City. The four victims died instantly at the scene, command duty officer Major Alden Brinas was quoted as saying in a report.

After the initial shooting, the gunman attempted to enter another room, but two other soldiers wrestled with the attacker, seized his firearm and shot him dead, Brinas said.

The critically wounded soldier was undergoing treatment at a local hospital, according to the officer.

Brinas did not mention what triggered the gunman to run amok. An investigation into the shooting incident is underway.

Army spokesperson Major Francisco Garello said the military is conducting its internal investigation "to look into all angles that triggered the incident".