Riots on successive days at a state prison in Mazatlán have resulted in the deaths of 11 inmates and a toddler who was part of a family visit, while another 16 inmates were injured.

According to reports from the Sinaloa Security Ministry (SSP), Thursday’s riot, which occurred during scheduled family visiting hours, began as a violent clash between inmates who managed to acquire and use firearms inside the facility.

When gunfire broke out in two contiguous units, prison officials locked down the facility and issued a red alert, but struggled to contain the fighting.

Elements of the Army, Navy, National Guard and state security forces were deployed to regain control, but not before 10 people were killed and 16 were injured.

State Security Minister Sinuhé Téllez confirmed that a 2-year-old boy was among the dead, while the injured were transferred to a medical facility for treatment.

The boy’s mother told investigators that she went to visit her husband, but left to pick up another child, leaving the boy in his father’s care. The boy’s father is reportedly among the 16 inmates hospitalized.

Inmates’ families gathered outside the prison, known as “El Castillo,” to demand information about their loved ones, while officials secured the scene inside.

State prosecutors and federal security agents have launched a formal investigation into how firearms were smuggled into the prison — two 9mm handguns were recovered after the incident — and are piecing together the exact sequence of events that triggered the confrontation.

The SSP will collaborate fully with the State Attorney General’s Office, Téllez said, in order to clarify the facts and determine if any prison employee was involved in allowing the weapons inside the facility.

The newspaper Diario de Yucatán said the shootout was allegedly aimed at assassinating Eduardo Jonathan Martínez Larios, alias “El Owen,” identified as a member of the Los Chapitos faction of the Sinaloa Cartel. He was reportedly among the dead.

Early Friday, another confrontation broke out within a single cellblock. The authorities quickly controlled the situation, but not before two inmates were killed.

In a social media post, the SSP said the rest of the prison population was safe, adding that the interinstitutional task force maintains a presence inside and outside the prison to preserve order and security.

Prison staff are in the process of establishing communication with inmates’ relatives to inform them about the situation and “will continue with follow-up to provide them with the necessary information.”

With reports from Reforma, Milenio, Diario de Yucatán and 24 Horas