At least three Marine soldiers were killed when they were ambushed by Abu Sayyaf terrorist group members in the Philippines' Sulu province on Thursday, officials said.The soldiers were assigned with the Marine Battalion Landing Team-10. Military officials declined to name the killed and said their families were yet to be notified, Xinhua news agency reported.The three soldiers were procuring supplies in Indanan town at 8 a.m. when they were waylaid by the militants, an official said.The soldiers were on foot and were not able to fire back at the attackers. The bodies of the slain troops were brought to Camp Teodulfo Bautista in Jolo town, the official added.Government soldiers have intensified operations against the Abu Sayyaf Group in Sulu and Basilan after President Rodrigo Duterte's pledge to wipe out the group.