Mayor Assassinated, 17 Others Dead After Cartel Members Open Fire Inside Town Hall in Mexico to Announce Return [GRAPHIC]

Armed Gunmen have shot dead the mayor of a small town in western Mexico, and at least 17 others, according to authorities.

Police say gunmen stormed the San Miguel Totolapan town hall on Wednesday afternoon and killed 18 people, including Mayor Mendoza Almeda, police officers and council workers.

Mayor, Mayor's Father Assassinated in the Attack

Mayor Conrado Mendoza Almeda
Mayor Conrado Mendoza Almeda and graphic images of the massacre's aftermath. Twitter

Mayor Conrado Mendoza Almeda's left-wing PRD party condemned his "cowardly" assassination and demanded justice. Almeda's father, former mayor Juan Mendoza Acosta, was killed at his residence before the attack continued at the town hall. The mayor's left-wing PRD party condemned his "cowardly" assassination and demanded justice.

A highway in the state of Guerrero, where San Miguel Totolapan lies, was reportedly briefly blocked by large vehicles to prevent security forces from getting into the city.

San Miguel Totolapan town hall shooting
The San Miguel Totolapan town hall riddled with bullet holes. Twitter

Photos circulating on social media show the town hall riddled with bullet holes. Graphic video footage has emerged of bloodied bodies strewn across the city hall floor as family members scream in horror. The following video is extremely graphic in nature. Viewer discretion is advised.

Another clip circulating online appeared to show the armed cartel members outside the town hall, with at least three people pinned to the ground.

Los Tequileros Claims Responsibility, Carried out Attack to Announce Return

The Los Tequileros criminal gang, which is linked to a powerful drug cartel, has claimed responsibility for the massacre. Shortly before the attack, alleged members of Los Tequileros released a video on social networks announcing its return to the region, where they had been fighting a rival drug gang.

San Miguel Totolapan lies in the heart of a region known as Tierra Caliente, a violent part of drug cartel-controlled western Mexico. Various groups battle for control of the lucrative drug routes north along the Pacific corridor, our correspondent adds.

The criminal group devastated Guerrero between 2015 and 2017 when Juan Mendoza Acosta was the town's mayor. The gang was known for threatening mayors of the region - until its leader Raybel Jacobo de Almonte was assassinated. De Almonte was known as El Tequilero - the Tequila Drinker - and his gang took their name from him.

Following the attack, the defence ministry said it was deploying army and navy units to the area to find the gunmen. Guerrero Governor Evelyn Salgado Pineda tweeted to say she deeply regretted the deaths.