The police on Friday took control of a prison riot, in which at least 16 prisoners were injured, El Salvador's National Civil Police (PNC) said.
The riot occurred in the Apanteos Prison in Santa Ana, around 60 km west of San Salvador, the police said. Five of the injured prisoners were taken to the national hospital of San Juan de Dios in Santa Ana.
The PNC denied it had used guns to control the riot, but people living near the prison told a local radio station that they heard shots.
The police has set up a security cordon around the prison.
The prisons in El Salvador have a combined accommodation capacity of 8,300 prisoners. However, they are overcrowded, housing some 20,600 inmates, including 7,000 gang members.