Querétaro Governor Mauricio Kuri told a news conference: “I have been informed that investigation files have already been opened, including for attempted homicide.”

Three people out of the 26 mostly male victims who were initially hospitalised have been discharged, while 10 are in “delicate” health and three others in critical condition, Kuri added.

Soccer fans on Saturday stormed the pitch during a top-flight match between mid-table Querétaro and last year’s Liga MX champions, Atlas. Social media images showed people being beaten, kicked and dragged in the seating area of the stadium.

Officials said people who appeared in photos lying on the ground, some covered in blood, were alive and being treated in hospital.

One man identified in a photo, in his twenties, was being treated for head trauma and light haemorrhaging, said Querétaro Health Minister Maria Perez.

The regional governing Confederation of North, Central America and Caribbean Association Football, which includes Mexico’s Liga MX, on Sunday called on authorities to investigate the attacks.

“The shocking acts of vandalism and violence that occurred last night in Querétaro, Mexico, have no place in soccer or in society,” the group said in a statement.

“The Confederation also believes that strong sporting sanctions should be applied,” it added.

Both the Querétaro and Atlas teams condemned the violence and urged investigations. Officials did not address what might have triggered the clashes.

Liga MX suspended Saturday’s match after 62 minutes, with visitors Atlas leading 1-0, and also called off planned games for Sunday.

(Reporting by Carlos Pacheco, Daina Beth Solomon and Adriana Barrera; Editing by Bill Berkrot)