Gunmen in a Philippine restive southern region opened fire on three boats and killed 15 people in what officials say was likely a clash between rival fishermen.
Military spokesman Lt Col Randolph Cagangbang said the attack took place off Sibago Island in Basilan province.
It is a stronghold of Muslim rebels who have been fighting for minority self-rule in the predominantly Christian nation for decades.
However, Cabangbang ruled out the involvement of al Qaida-linked Abu Sayyaf militants who were blamed for a series of deadly attacks on civilians and troops last year.
He said the fishermen were probably attacked by a rival group because they strayed into their fishing grounds.
Three other fishermen were wounded.