ZAMBOANGA CITY: Security forces on Monday detonated a homemade bomb planted on a highway in Tacurong City, Sultan Kudarat. Police said the explosive, placed in a cardboard box, was found with blasting caps and attached to a cell phone. No individual or group claimed responsibility for the foiled bombing, but the province is a known stronghold of rebel groups fighting for a separate Islamic state in the restive southern Philippines. Last year, two unidentified men on a motorcycle also exploded a fragmentation grenade at police headquarters in Tacurong City. Earlier, police also disarmed an improvised explosive planted in a bus travelling to Koronadal City in South Cotabato also from Tacurong City.