At least 28 inmates have been killed in a brutal prison fight in the Mexican Pacific resort city of Acapulco.
It's one of the worst outbreaks of violence in the country's troubled penal system in recent years.
Acapulco is the biggest city in Guerrero, one of Mexico's most lawless states and a center for opium poppy production.
A state security official Roberto Alvarez told reporters that the fight broke out between rival gangs in the maximum security wing of the jail.
Bodies were found throughout the area, including inside and outside the kitchen, as well as the area designated for conjugal visits.
The prison riot came on the same day that the U.S. Department of Homeland Security Secretary John Kelly was visiting Guerrero, which lies in the southwest of the country.
Kelly has been discussing co-operation on combating organized crimes with his Mexican counterparts as well as the President Enrique Pena Nieto.
The killings in Acapulco are the latest in an upsurge in violent crime that has turned 2017 into one of the bloodiest in the country's modern history.
Acapulco has been roiled by vicious gang warfare, and is now ranked as one of the most murderous cities in the world.