NATION IN BRIEF : MASSACHUSETTS : Violence Erupts as Show Is Canceled

A music and comedy show at City Hall Plaza in Boston erupted in violence after members of a crowd of about 20,000 became enraged when police ordered the show halted because of unruly behavior. At least 16 people were hurt, including a 16-year-old boy who was stabbed in the stomach. Eighteen people were arrested. After the show was canceled, hundreds of people spilled out into a nearby neighborhood, smashing windows of cars and stores and vandalizing stores, police said. Scheduled to appear were Mr. Big, Meli’sa Morgan, Stacy Earl, M.C. Brains and Arrested Development.