Awwal 28, 1432 H/March 3, 2011, SPA -- Five people were wounded Thursday in a roadside bombing suspected to have been perpetrated by extortion gangs in the southern Philippines, police said. According to dpa, the homemade bomb exploded as a bus passed along the highway in Kayaga town in Pandag town in Maguindanao province, 960 kilometres south of Manila. The bomb was made from a 60-millimetre mortar shell attached to a mobile phone that served as a trigger mechanism, the town's police chief said. Senior Inspector Mark Donald Edquibal said four passengers, including a government militiaman, and the bus conductor suffered various injuries. "No one has claimed responsibility for the bombing but we have several suspects including known extortion gangs," he said. An extortion syndicate called Al-Khobar has been blamed for numerous bombing attacks on buses in the southern Philippines in recent years, killing dozens of people.