A prison riot in Mexico reportedly provoked by an inter-inmate football match left at least 16 dead and five wounded, authorities have confirmed.
The Centre for Social Reintegration (Cereso) of Cieneguillas Prison, located in the state of Zacatecas, was rocked on Tuesday by bloody clashes between prisoners.
And the spark for the riot appears to have been a game of football, organised between imprisoned members of two rival drug cartels: the Gulf cartel, and a faction of the Zetas.
According to Zacatecas security secretary, Ismael Camberos Hernandez, several weapons were confiscated in the aftermath of the clash, which authorities believe were smuggled into the prison during Tuesday's visiting hours.
Hernandez added that searches over the weekend had not found any guns among inmates.
The state security agency explained that the deadly battle commenced around 2.30 pm on Tuesday, with the prison brought back under control just under three hours later.
"The Cereso emergency systems were activated, a fight between inmates with firearms was reported," Camberos told reporters.
"Gunshots were heard and the state police and Metropol immediately began an operation to control the fight, which the centre's guards were already trying to quell."
Fifteen of the deceased were killed at the prison, with another passing away after being rushed to hospital due to the extent of his injuries.
Camberos went on to reveal that as well as gunshot wounds, victims were also stabbed and hit with blunt objects.
No guards or security officers were hurt in the melee, while one prisoner was detained in possession of a firearm and three more guns were later found on the premises.
At the time of writing, no motive has been named regarding the cause of the riot, but clashes between rival gangs have taken place on numerous occasions in Mexican prisons in recent years.
Nueva Leon state's Topo Chico facility, which was closed earlier this year after countless complaints concerning sub-standard living conditions for inmates, was infamous for violence within its walls.
In 2012, three prisoners were stabbed to death in targeted attacks, while four years later 49 prisoners lost their lives in another bloody battle between the Gulf cartel and the Zetas.