Gunmen attack fishing boats in Philippines, killing 15 January 24, 2012 -- Updated 0728 GMT (1528 HKT) Unidentified gunmen attack three fishing boats in the region of Mindanao The attack kills 15 fishermen and wounds 3, the military says The authorities say they believe the attack is part of a turf dispute between fishermen The military rules out the involvement of Muslim separatists (CNN) -- Gun-wielding attackers aboard small vessels opened fire on a group of fishing boats in a restive area of the southern Philippines, killing 15 people in an apparent turf dispute between fishermen, the military authorities said Tuesday. The three fishing boats from the large island of Mindanao were near the tiny island of Sibago when they were attacked Monday morning by about six men on three smaller craft, said Col. Arnulfo Marcelo Burgos, a spokesman for the Armed Forces of the Philippines. Sibago is off the west coast of Mindanao, close to the island of Basilan. "Local fishermen claim turf rights over the area," Burgos said, adding that the military was coordinating with the police in pursuing the perpetrators. The Mindanao group of islands includes a Muslim autonomous region that was set up in the 1990s to quell armed uprisings by people seeking an independent Muslim homeland in the Philippines, a predominantly Christian country. Basilan is part of the autonomous region and separatist groups like Abu Sayyaf have been known to operate there. But Burgos said the military did not suspect the involvement of such groups in the killing of the fishermen on Monday. The attack left three fishermen wounded, he said.