Shipping lines crossing Zamboanga del Sur and the Moro Gulf near the Philippine island of Mindanao should exercise caution after pirates robbed a fishing boat and killed eight crew, Interaksyon reported.

Security forces are hunting the gunmen, who attacked around 8pm on Monday as the vessel was returning to port, the news service said. Mindanao has a history of violence and lawlessness, and hosts an array of communist and Islamist armed groups, bandits and private militias.

“We consider this a piracy attack. If these were Islamist militants, they would have been taken captive and held for ransom,” Interaksyon cited Coast guard spokesman Commander Armand Balilo as saying.

The attack may have been an offshoot of a “rido,” or clan war, the report said, citing an army spokesman.

Two survivors were rescued by passing fishermen, while seven others managed to jump overboard and swim to safety, it said.