At least eight people, including three children, were killed and 79 were wounded when a monster truck careened into a crowd at a show in northern Mexico, an official at the public prosecutor's office in the city of Chihuahua said on Sunday.
The incident late on Saturday afternoon took place at the El Rejon dam on the outskirts of the city, about 230 miles (370 km) south of Mexico's border with the United States.
Some local media reported the death toll had risen to 13, but there was no official confirmation.
The dead included two girls aged 6 and 7 and a 12-year-old boy, according to the city government's official Facebook page. Some 46 people remained in hospital on Sunday morning after 33 were discharged.
A preliminary investigation suggested the accident was due to a "technical error," the official said, adding the driver has been detained.