Four men were sent to the hospital after a fight at the Cook County jail, according to authorities.
A fight broke out between rival gangs in the maximum-security division, according to Cook County Sheriff's Office Spokeswoman Sophia Ansari.
Four men were taken to Stroger Hospital in stable condition, according to the fire department. Three others were treated at the jail, Ansari said.
A ball point pen was used as a weapon in the altercation, Ansari said.
No other details were immediately available.