The Philippines and Malaysia will hold naval drills this week in seas that have become hunting grounds for the notorious Abu Sayyaf terrorist group, human traffickers and smugglers.
In an advisory, Naval Forces Western Mindanao said live-fire and interoperability exercises will be held in waters around the Zamboanga peninsula, and in seas separating Sulu province in the southern Philippine island of Mindanao and Malaysia's Sabah state.
The drills - the 19th to be held since the Philippines and Malaysia signed a defence cooperation agreement in 1994 - will begin today and last till Friday. "The focus is on maritime security and transnational crimes," said Philippine Navy spokesman Chester Ian Ramos.
The joint exercises will involve ships, aircraft and special units from the Philippine Navy and Royal Malaysian Navy. The navy advisory did not say how many troops or what ships will participate in the drills, but at least 300 Filipino and Malaysian soldiers and sailors had participated in previous exercises.
The Abu Sayyaf, a group formed by disgruntled Islamist fighters in 1991 with Al-Qaeda funding, has been hunting in waters off Sulu for tourists and traders in Sabah.
Some 400km of open sea separates Sulu and Sabah.
Despite a floating force that Malaysia deployed just outside Sulu's waters, the Abu Sayyaf, human traffickers and smugglers have been able to criss-cross the porous border. Last week, US-trained Philippine commandos raided an Abu Sayyaf lair on Jolo island in Sulu to free hostages held there, including two Malaysians taken from Sandakan in Sabah on May 14.
Two Philippine Coast Guard personnel held hostage since May 4 managed to flee during the fighting.
But the fate of nine other hostages - including Malaysians Thien Nyuk Fun, 50, manager of a seafood restaurant in Sandakan, and Bernard Then Ted Fen, 39, an engineer - remained unknown.
The Abu Sayyaf gained prominence in May 2000 when it attacked a dive resort in Sipadan, Sabah, taking 21 hostages.
Over the years, US-backed military campaigns had managed to decimate the group's leadership.
In recent years, however, it has managed to regain some of its strength from ransoms it managed to raise from traders it kidnapped in Sabah and Mindanao.