A bus carrying cruise ship tourists tumbled down a mountain ravine in northern Chile Wednesday, killing 11 people, including some believed to be US citizens, officials said. Several other passengers were injured in the crash along a rugged highway near the Pacific port city of Arica, 1,250 miles north of Santiago, said Juan Carlos Poli, an Arica city hall spokesman. "Rescue crews are working in the area, but we have confirmed 11 people killed, most of them apparently from the United States," Poli said. He did not have an exact number or identities of the victims. Regional governor Patricia Perez said a preliminary report by police put the number of injured at 5.