MANILA, March 2 (Xinhua) -- Six people were injured Saturday night in a bomb attack in front of a military base in the island province of Sulu, southern Philippines, where government troops and U.S. troops have just completed a joint military exercise, reported the official Philippines News Agency on Sunday.

    Local police said the explosion took place inside a bar in front of a major military camp where soldiers frequent, said the report, adding that among the injured were two soldiers and four women.

    Police said although no one has claimed responsibility over the attack, the type of explosive that was used "carries the signature" of Abu Sayyaf rebels.

    It is an improvised explosive device consisting of a mortar shell with a primer that is usually used in the terrorist acts by the Abu Sayyaf group, said the report.

    Located 900 kilometers south of Manila, Sulu is considered a stronghold of Abu Sayyaf rebels who have been waging a guerrilla war against U.S.-supported government forces since 1990s.