Seven inmates died Friday and a further 59 managed to escape a prison in the northern Mexican city of Nuevo Laredo after a fight broke out, dpa reported.
The government of the state of Tamaulipas said five guards left their positions during the clash at a ward that holds more than 1,200 inmates.
Of the fugitives, 35 were being held for federal crimes including drug trafficking, while the rest were regarded as common criminals.
"The situation is currently under control and events are being investigated in a coordinated fashion by local and federal authorities," Tamaulipas authorities said in a statement.
Federal and state police officers were seeking the runaways as well as the deserter-guards. Nuevo Laredo is across the border from the US city of Laredo, Texas.