Philippine President Rodrigo Duterte on Tuesday said he had asked China to send naval or coast guard ships to patrol international waters off the southern Philippines to help in the fight against piracy.

In an address to military officers, the Philippine leader said he "asked China if they can patrol the international waters without necessarily intruding into the territorial waters of countries," referring specifically to the Sulu Sea between Mindanao and Borneo.

"We would be glad if we have their presence there," he added.