A riot at a maximum-security prison in western El Salvador left at least 20 inmates dead on Saturday, officials said. Deputy police director Luis Tobar Prieto said officials had regained control of the prison in Apanteos, 70 kilometers (40 miles) west of the capital of San Salvador. The 20 dead were all prisoners and several people were injured, none seriously, he said. The riot began late Friday as inmates prepared to enter their cells, authorities said. A jailed gang member grabbed a guard he had been arguing with, and other prisoners began fighting and tearing down the prison's flimsy interior walls. Guards then fled as hundred of inmates battled each other.