At least 21 people were killed in a gunfight between armed civilians and the Mexican security sources near the U.S. border in northern Mexico, according to local media on Sunday.

An hour-long gun battle took place in Villa Union, a town in Coahuila state, Miguel Angel Riquelme, the state governor told local media.

Riquelme said the armed assailants attacked the local administration offices and federal security forces responded immediately.

A total of 21 people, including four policemen, lost their lives in the incident.

The armed assailants are thought to be alleged members of the Cartel of the Northeast, a gang involved in drug trafficking.

Videos and images of the shootout shared on social media showed vehicles set ablaze and the facade of Villa Union’s municipal office pierced with bullets.

Mexico has long been besieged by deadly violence with drug cartels and criminal gangs fighting for control of territories.

The total number of victims of violent killings since President Andres Manuel Lopez Obrador took office in December 2018 is approaching 20,000, according to the country's National Public Security System.

(Anadolu Agency)