At least 10 people have died and 20 have escaped after a riot at a prison in Juárez, Mexico: NPR

At least 20 escaped inmates are now free after a riot at one of Mexico’s most notorious prisons turned into a deadly escape on Sunday. At least 10 people were killed.

The district attorney said in a statement that the Mexican army, national guard and local police now had the situation under control by Sunday afternoon.

The prison riot took place in Ciudad Juárez, a northern border town plagued by cartel violence. Juárez Mayor Cruz Pérez Cuéllar told local media that gunmen entered the prison.

Cereso State Prison, located in the city, is considered one of the most dangerous institutions in Latin America. Deadly prison riots are commonplace: including one in 2009, where 20 people died, and another in 2011, where 17 people died.

In August, soldiers from the Mexican army and national guard were called in for help after three people were killed in a gang fight in prison, according to the El Paso Times.

Government officials said the prison is known to be run by members of an organized crime group known as the Mexicles. Over the years, this group has planned and ordered attacks on the city of Juárez from inside the prison, officials say.

Mexican media reported that 10 prison guards were killed along with four inmates.

The Diary shared images of smoke billowing from the jail, while residents said they heard heavy gunfire.

Eyder Peralta contributed reporting.