Gunmen have killed 15 Philippine fishermen and wounded three others in a sea attack by suspected local rivals, the military said Tuesday.
The fishermen were killed by men armed with assault rifles off the insurgency-torn southern island of Basilan on Monday, regional military spokesman Lieutenant-Colonel Randolph Cabangbang told AFP.
"They (victims) were fishing on another group's turf," Cabangbang told AFP in a telephone interview.
He said the authorities had ruled out the potential involvement of Islamist militants or Muslim guerrillas, who are also active in Basilan.
No group has claimed responsibility for the attack, but police have identified several suspects and arrests are expected shortly, Cabangbang said.
A military unit was ordered to provide security for police investigators as well as to help track down the suspects, described by the authorities as heavily armed.
"There is an operation to track down the attackers, who could also be fishermen. This attack could be connected to a turf war," said regional military commander Major-General Noel Coballes.
The victims were all residents of the southern city of Pagadian, about 160 kilometres (100 miles) to the northeast, and were attacked as soon as their three boats approached the tiny island of Sibago, off Basilan's east coast.
Other fishermen in the area later discovered the shooting and took the three wounded victims to hospital, Cabangbang said.
The bodies of the 15 dead fishermen were taken back to Pagadian, he added.
Rights groups have said a culture of impunity pervades the Philippines, where there are more than 1.1 million unlicensed firearms, on top of the 1.3 million guns in the hands of authorised police and military personnel.
The combined tally means there is roughly one firearm for every 40 Filipinos.