Two adults and one child were struck by a vehicle on 35th Avenue and Greenway Road, fire officials said.
According to the Phoenix Fire Department, all individuals were taken to hospitals for treatment in critical condition; the individuals were not using a crosswalk.
The young girl, who is between the ages of four and five, sustained back and neck injuries; she was awake while she was transported to a hospital. Fire officials said the man sustained superficial injuries while the woman sustained internal injuries; both are in their late 50s.
Phoenix police also said the occupants inside the suspect vehicle fled the scene. A person who claimed to be the driver of the vehicle has turned himself into police at the Cactus Park Precinct.
Police told ABC15 the suspected driver's mother took her son to the precinct; officials at the scene said the man was driving his mother's car.
Police believe a passenger of the suspect vehicle may still be at large.
Traffic was closed down in the area for the investigation.
No other information is currently available. Stay with ABC15 for updates.