MANILA (AFP) - Two Islamic militants linked to the abductions of 26 Malaysian and Indonesian sailors this year were killed Tuesday (Sept 27) in a military raid off a remote Philippine island, Manila said.

Nixon Muktadil and his brother Brown Muktadil, both members of the Abu Sayyaf group, died in "strike operations" by an anti-terror task force at dawn, a Philippine military statement said.

The Abu Sayyaf is a loose network of militants formed in the 1990s with seed money from Osama bin Laden's Al-Qaeda network that has earned millions of dollars from kidnappings-for-ransom.

While its leaders have in recent years pledged allegiance to the Islamic State in Iraq and Syria (ISIS) group, analysts say the group is mainly focused on a lucrative kidnapping business rather than religious ideology.

"The death of the Muktadil brothers is a major blow to the group... because they serve(d) as the sea guides and navigators during (the) conduct of kidnapping at the high seas," the military statement said.

The brothers helped snatch crew members of five tugboats carrying coal and other commodities on waters bordering Indonesia, Malaysia and the Philippines, it said.

The kidnappings took place over a six month period earlier this year, the military added.

The spike in abductions sparked Indonesian warnings that the region could become the "next Somalia" and pushed the three neighbours to pledge coordinated patrols.

Most of the 26 sailors are thought to have been released but the Philippine government has said the Abu Sayyaf is still holding five Indonesian hostages - although it is not clear if they include any of the sailors.

The militant group freed four Indonesians earlier this month and a Norwegian hostage. It beheaded two Canadian captives and released Indonesian and Malaysian sailors in batches earlier in the year.

The military operation Tuesday occurred off Tambulian island in the Sulu island group, a mainly-Muslim archipelago and Abu Sayyaf stronghold about 1,000km south of Manila.

Separately, police announced Tuesday they had arrested in Manila a Sulu politician accused of having sold government-issue guns to the Abu Sayyaf.

The raid Saturday on the house of Unding Kenneth Isa, turned up grenades, assault rifles and thousands of rounds of ammunition, most of them government-issue weapons.

Isa, who ran for vice governor of Sulu in May elections but lost, is accused of sending weapons by ferry to the Abu Sayyaf and other armed groups in the south, police said.