Officers say the two vehicles raced east on Gettysburg from Cedar to Jackson Avenues when one of the cars crashed off the road.
Investigators found shell casings in the vehicle and a replica gun nearby. One person has been detained, and no one appeared to be injured.
The driver of the second vehicle drove away from the scene. Officials described it as a light-colored Acura.
Anyone with information is asked to contact the Fresno Police Department.