Over the weekend, a Mexican border city was the site of a massive, deadly jailbreak.

On Sunday, gunmen who arrived in armored vehicles opened fire on a state prison in the border city of Ciudad Juarez, Chihuahua, just across the border from El Paso, Texas.

In the ensuing gun battle, 17 people — 10 of whom were prison staff — were killed, while 15 people — all but one of them prisoners — were also injured. Twenty-five prisoners escaped amid the melee, according to national security head Rosa Icela Rodriguez.

Among them were leaders and members of a criminal organization affiliated with the Cartel de Caborca, which has a significant presence in northwestern Sonora.