Dozens of inmates at are feared dead as a fire broke out during a riot at a Mexican prison, local media reported. Black smoke can be seen plummeting from the Topo Chico prison near Monterrey in images from the scene uploaded online.

The blaze was caused by detainees, who set alight mattresses during a massive melee and within the prison walls, according to Mexican daily Excelsior. The newspaper says some prisoners tried to escape as chaos unfolded at the detention facility in Nuevo Leon state at around midnight local time on Thursday (11 February).

Relatives have gathered outside the penitentiary bundled against the cold, waiting for news on their dear ones. Unconfirmed reports say up to 50 people might have died and 70 were injured.

Security forces and emergency services are at the scene.