A fight inside the El Castillo prison in Mazatlan, in Mexico's northwestern state of Sinaloa, left ten people dead and 16 injured, state authorities said on Thursday. The dead were nine inmates and a minor who was visiting a family member; security forces have since regained control and visits have been suspended. Sinaloa (a Pacific-coast state and the home of the Sinaloa drug cartel) is gripped by fighting between rival cartel factions, though officials have not said whether the prison violence was linked to that conflict.