The military said the ambush happened at about 7:30am [23:30 GMT] on the southern island of Jolo near Maimbung town.
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Philippines on the brink

Regional military commander Major-General Eugenio Cedo ordered troops to pursue the attackers on Jolo, where US-backed forces have been hunting remnants of the Abu Sayyaf, which the US calls a terrorist organisation.
Helicopters flew to the scene of the fighting to ferry troops and bring back the wounded.