Philippines president Rodrigo Duterte has said Indonesian and Malaysian troops can bomb retreating Abu Sayyaf militants and their seafarer hostages.

He said action could be taken at sea because the captive crew from tugs "are not supposed to be there," the Tempo daily reported.

Duterte said he had told Malaysian prime minister Najib Razak and Indonesian president Joko Widodo that their forces could enter Philippine waters in pursuit of the militant group.

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