(Updates number beheaded, adds more details) JOLO, Philippines, April 19 (Reuters) - Muslim extremists decapitated seven men they were holding hostage on the southern Philippine island of Jolo and sent the heads in sacks to two army detachments, the military said on Thursday. "This is a terrorist act that should be condemned by all," Major-General Ruben Rafael, commander of military forces on Jolo, said. Earlier, Rafael said his soldiers had discovered the headless bodies of six men close to Parang town, where they had been kidnapped on Monday by the Abu Sayyaf, the Philippines' deadliest Muslim rebel group. A seventh man was kidnapped in the area earlier that day. Rafael said Abu Sayyaf may have beheaded the men in retaliation for the military killing over 70 of its members, including two top leaders, in an eight-month ground offensive backed by U.S. advisers and equipment. The Abu Sayyaf gained international notoriety around five years ago when they captured and beheaded tourists and church workers, and its members still kidnap people for ransom to raise funds. They decapitated the son of a wealthy trader last year. This week, the group had demanded a 5 million peso ($105,000) payment for the release of six of the men, who were working on a government road project and taken at gunpoint from their truck. The Philippines has poured over 8,000 troops onto Jolo to flush out the Abu Sayyaf and members of regional terrorist network Jemaah Islamiah who use the island's remote mountains to train and plot. The Abu Sayyaf, with an estimated force of around 400 fighters, carried out the Philippines' worst terrorist attack, the bombing of a ferry near Manila in 2004 that killed over 100 people.
