Fifty people have been reported killed and a further 70 injured after a riot erupted at Topo Chico prison, northeastern Mexico on Thursday as a group of inmates apparently attempted a jailbreak.
Prisoners are said to have taken over parts of the prison in the early hours of Thursday morning, reports Milenio TV.
Witnesses have described how explosions could be heard coming from inside one of the buildings in the complex.
Local media say a fire subsequently broke out at the facility, with unofficial reports of 50 prison staff and inmates killed in the riot.
The eruption of violence led to the deployment of the Mexican army and police to the area.
Topo Chico prison authorities have not made an official statement on the riot. However, the Nuevo León state government has posted on Twitter, saying the situation was under control at 1.30am local time - approximately 90 minutes after the disturbance began.
No prisoners have escaped the grounds of the prison and state authorities say they are now working to provide information to families of the inmates.
Earlier, images from the scene showed flames and smoke billowing from the building, as prisoners appeared to gather in an outside fenced area of the jail.
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