DENTON, Texas (CBSDFW.COM) – After hours of surgery and continued medical care from doctors at Medical City Hospital, a Denton police officer remains in the intensive care unit.

The officer, whose name has not been released, was critically wounded after being shot during a traffic stop not far from the University of North Texas campus on Tuesday morning.

The incident happened just after midnight in the parking lot of a Taco Bell on University Drive. On audio from a police radio call the yell “Shots fired! Shots fired! Officer down! Officer down! Vehicle getting away,” could be heard.

At an early morning news conference Denton Assistant Police Chief Bobby Smith said the officer was attempting to pull over a driver for an equipment violation. “During the course of a traffic stop an officer was shot,” he said. “Backup officers at the scene were there and returned fire. The suspects fled the scene and the officer was transported to the hospital.”

The suspects fled the scene in a Chevy Malibu, but police in Carrollton spotted the car after a be-on-the-lookout alert was broadcast. Police there chased the vehicle after the drive refused to stop and took off along Sandy Lake Road.

The chase weaved thorough Carrollton and down the George Bush Turnpike before the suspects ultimately pulled into a RaceTrac gas station on Valley View Lane at Luna Road.

As officers took a man and a woman into custody from inside the vehicle they discovered that both had been shot. The suspects, whose names also have not been released, were arrested and taken to Parkland Hospital to be treated. Their current conditions are not known.

Carrollton police say their officers never discharged their weapons and Denton Asst. Chief Smith said officers in his department did fire at the suspects, but it wasn’t clear if it was their shots that injured the suspects.

The injured officer was is in critical but stable condition before undergoing surgery at Medical City Hospital in Denton, and is now said to still be in critical condition after hours on the operating table.

The Texas Rangers are leading the investigation and are being assisted by the Major Crimes Unit of the Denton Police Department.