A prison riot in the eastern Mexican state of Veracruz led to 7 people dead and 11 others wounded, regional authorities said Sunday.

What do we know so far?

The riot broke out at the Taxpan prison in the city of the same name. Videos circulating on social media showed fires at the penal facility and plumes of smoke rising from the prison grounds.  

"As a result of the riot, we report the tragic deaths of seven inmates and 11 injured people," the Department of Public Security of Veracruz said in a statement. Police and security forces intervened to quell the unrest at the prison.   

The riot reportedly broke out on Saturday after inmates expressed anger over extortion and abuse by members of the Grupo Sombra criminal organization at the prison.

A 2012 report by Mexico's human rights commission found that six out of 10 Mexican prisons are controlled by either prison gangs or drug cartels. Mexican prisons also face other issues such as overcrowding and corruption. 

The Tuxpan prison had 778 inmates in June, exceeding the 735 prisoners it was designed to hold. 

Who is Grupo Sombra? 

According to Mexican newspaper Milenio, Grupo Sombra made its first public appearance in 2017, when its hitmen gave frozen turkeys and soda to residents in Veracruz for Christmas that year.

Armed masked men forced women to smile for the camera and men had to give a thumbs up in a photo posted online to show gratitude for the "gift."

More recently, Grupo Sombra was linked to the femicide of a 65-year-old retired teacher in July.   

Milenio reported that Grupo Sombra consider themselves a splinter group of the Gulf Cartel, and that they aim to fight the Los Zetas syndicate and Jalisco New Generation Cartel (CJNG) in Veracruz. Grupo Sombra also claim to engage in social work that the Mexican government doesn't do. 

Edited by: Rana Taha