The southern Philippines is peppered with hotspots, and one detonated last week on the remote island of Jolo, where the Philippine army and marines fought rebels in three towns, and Air Force planes dropped 500-pound bombs on their strongholds in the island's thick jungles. It was the most intense fighting in the south in at least 30 years and by week's end, 22 soldiers had been killed, along with 60 rebels. Southern Command Chief Lieut. General Alberto Braganza said that several dozen American troops had been sent in from their base in the southern city of Zamboanga, although he insisted the Americans wouldn't be fighting, but merely acting as intelligence trainers. A rebel attack on the capital city of Jolo was feared, but Braganza said his men would continue to fight. "There will be no let-up," he vowed. "What they started, I will finish."There are two versions of how the hostilities began. The military says 14 of its troops were ambushed and killed on Feb. 7 in the town of Panamao. The rebels say that the ambush was provoked by a military offensive the day before in which a local ustadz, or religious mentor, his wife and two children died. (The military is silent on that story.) The rebels include members of Abu Sayyaf, an al-Qaeda linked kidnap-for-ransom group, and renegades of the Moro National Liberation Front (M.N.L.F.), a Muslim group that once fought for a separate state. The military estimates the rebels' numbers at 800. By the end of the week, the armed forces had sent seven battalions—roughly 3,000 soldiers—to the island.