Four people, including two police officers, were killed in a clash in the southern Philippines that was sparked when police confronted a man carrying an assault rifle, a provincial police chief said Thursday.

The fighting erupted Wednesday when companions of the gunman fired at the police officers, triggering a fire-fight that lasted for about one hour in Sumisip town in Basilan province, 900 kilometres south of Manila, Senior Superintendent Antonio Mendoza said.

Police officers recovered four assault rifles left behind by the fleeing gunmen, Mendoza said, adding that more troops were dispatched to the area to pursue them.

Mendoza said authorities could not immediately identify the gunmen but an investigation was being conducted.

Basilan is a known haven of al-Qaeda-linked Muslim Abu Sayyaf rebels and Muslim separatist rebels. Criminal groups are also known to operate in the area.

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