A tractor-trailer slammed into a bus carrying Canadian and US tourists in northern Mexico, killing 11, officials said Tuesday. Coahuila state police commander Armando Santana said some Americans were among the dead but could not say how many. He said the bus was carrying a group of Texas retirees from McAllen, Texas, to the northern Mexican state of Zacatecas when it crashed Monday. Fifteen people were hospitalized with serious injuries. Canadian foreign affairs spokesman Alain Cacchione said Canadians were involved in the accident but he declined to provide further details for privacy reasons.