CHICAGO (WBBM)  -- A fight between about 40 Cook County Jail inmates Tuesday morning left 11 guards and seven inmates injured.

The fight started about 9:15 a.m. in the yard at Division I of the jail at 2750 S. California Ave., according to Cook County Sheriff's police spokeswoman Penny Mateck.

There were 218 inmates in the yard when a gang-related fight broke out, Mateck said. Approximately 40 inmates were involved in the fight, though no weapons were found among the participants, Mateck said. "It was purely a fistfight."

"Eleven of our officers were injured while breaking up the fight," she said. Of the injured guards, eight were treated at the scene, two were treated at Cermak Hospital on the jail grounds and one was taken to another hospital. None of the guards suffered life-threatening injuries.

Seven inmates were injured -- five were treated at the scene and two were taken to John H. Stroger Jr. Hospital of Cook County, Mateck said. None of the inmates' injuries were believed to be life-threatening.