Eight people have been shot dead in an attack Monday on a fishing boat in the southern Philippines, a military official said Tuesday.

The fishing boat manned by 15 people was attacked by an armed group at night off the coast of Laud Siromon Island in Zamboanga province, said Col. Juvy Max Uy, commander of a military taskforce in the province.

He said a contingent of Philippine Marines has been sent to secure the area while local police hunt for the five unidentified suspects.

"These are lawless elements," Uy said, citing extortion as a possible motive behind the boat attack, which seven crew members survived after reportedly jumping off the boat.

Concerns have grown over piracy and crew abductions by pirates in waters stretching between eastern Malaysia and the southern Philippines, leading those two countries plus Indonesia to beef up maritime security cooperation.

According to a report issued Tuesday by Kuala Lumpur-based Piracy Reporting Center of the International Maritime Bureau's, 28 crew members were kidnapped from ships in the area, including ocean-going merchant vessels and slow-moving tugs and barges.

Some of them were then transferred to the southern Philippines and held for ransom by armed men linked to the Abu Sayyaf terror group, which is based in the country's restive Mindanao region.