At least 52 people were killed and 12 people were wounded in a prison riot in the Mexican city of Monterrey, the governor of the northeastern state of Nuevo Leon has said.

Governor Jaime Rodriguez said on Thursday the riot in the Topo Chico prison involved a faction led by a member of the infamous Zetas drug cartel.

Images broadcast by Milenio TV showed police vehicles patrolling the streets near the prison after unrest broke out in the early hours of Thursday local time.

Milenio TV reported that relatives who visited prisoners in the jail had heard gunshots and said that a blaze had broken out.

They also said that they had seen inmates with burns and that authorities were hunting for escapees.

Witnesses said the fire broke out at about 1230am (0630 GMT) and appeared to have been extinguished shortly after sunrise, the Associated Press reported.

Earlier, local media had said the casualties included inmates and prison guards.

Families of the inmates rushed to the prison after reports of deaths. Some shook and kicked at the prison gates, demanding to be allowed in.

Al Jazeera