Al Qaeda-linked militants in police uniforms set off bombs and fired at civilians on a strife-torn Philippine island Tuesday in violence that left 15 people dead, officials said. The gunmen targeted a government office and a church in Isabela city on Basilan island with two homemade bombs, in the latest show of force from the Abu Sayyaf network that is blamed for the worst attacks in the Philippines. Isabela city mayor Cherry Akbar told reporters that 15 people were confirmed dead, including five militants who were apparently killed by one of their own bomb blasts. Six civilians were also killed in the explosions, while three soldiers and one policemen were killed in gunbattles with the militants, Akbar said.