Security forces fired shots in the air and used water cannons and tear gas to disperse about 2,000 angry Muslim youths rioting in Thailand's troubled south Monday, leaving at least one person dead and more than 20 injured, hospital officials said. A protest to demand the release of six detained security guards turned violent earlier Monday, with demonstrators hurling rocks at a police station in southern Narathiwat province's Takbai district and overturning a military truck.