At least 18 inmates were killed and 16 wounded during a fight between rival gangs in a Honduran penitentiary on Friday, authorities said, in one of the worst recent outbreaks of prison violence in the country. Two days earlier, the government declared a state of emergency in the prison system, transferring control to security forces in a bid to clamp down on a recent wave of violence. Fights in Honduras’ overcrowded prisons are frequent as street gangs vie for control inside the institutions.