Residents evacuate their homes at Ampatuan town, Maguindanao province, southern Philippines. Gunmen from a breakaway rebel group attacked army outposts in the southern Philippines, sparking clashes and shattering years of calm in the notoriously violent region. — AP MANILA — Suspected militants from a breakaway rebel group have set off bombs in the southern Philippines but failed to inflict injuries or disrupt army assaults against its fighters, who went on a rampage last week and sparked clashes that killed 28 people. Hundreds of troops, backed by helicopters, tanks and artillery fire, have forced armed fighters of the Bangsamoro Islamic Freedom Movement out of two strongholds and were pursuing them mostly in hinterland areas of Maguindanao province Sunday, officials said. The army is trying to drive the gunmen away from a major highway, which was closed last week to protect commuters from rebel sniper fire. At least seven homemade bombs have exploded in recent days along roads and in villages in Maguindanao and nearby North Cotabato province in an apparent attempt by the breakaway rebels to divert the army's focus from ongoing assaults. But the army assaults have proceeded despite the bombings mostly in isolated roads, including four blasts late Friday and Saturday, army officials said. “We believe these were diversionary attacks,” said deputy regional military commander Commodore Romeo Santiago Nebres, adding troops have strengthened security in public areas and of power transmission towers, two of which have been damaged by rebel bombs. Authorities were preparing criminal complaints against Ameril Umbra Kato, the ailing leader of the breakaway rebels and his known commanders, who attacked army camps and outposts and communities last week, Nebres said. The attacks killed four soldiers and three civilians and sparked clashes that initially killed four rebels. Hundreds of troops later assaulted and pursued the rebels, killing at least 16 more of the fleeing militants, who tried to slow down the advancing soldiers with sniper fire. Suspected rebel snipers killed a police officer guarding a highway in Maguindanao's Datu Unsay town Saturday, the military said. The clashes, which shattered years of relative calm in the volatile southern region, forced more than 39,000 villagers to flee from homes, according to the government's Office of Civil Defense. Village guard Roger Apenida said the rebels descended on his farming village in Maguindanao's Ampatuan town early last week and held him and dozens of other villagers hostage for a day before allowing them to flee when army troops approached. The gunmen seized 32 cell phones from the residents then destroyed bottles of liquor, a billiard table and a karaoke machine in three stores. “The rebels told us such vices as liquor were banned under Islamic laws,” said Apenida, who has taken refuge in an evacuation center in a nearby Ampatuan village. — AP