A Montgomery County police officer shot and wounded a 17-year-old Northwest Washington youth early yesterday. Police said the shooting occurred as the youth and a 16-year-old companion ran their car into Sgt. James D. Arnold.

The youth was reported in stable but critical condition in Suburban Hospital's intensive care unit yesterday. The officer was treated at Montgomery General Hospital for bruises on the left leg and released.

Police spokesman Sgt. Harry Geehreng said three members of a special undercover team had staked out businesses on Georgia Avenue in Wheaton after several burglaries.

About 4:50 a.m., Geehreng said, the officers saw two youths carrying a cinder block approach the window of a Radio Shack store. While police watched, anticipating a burglary, Geehreng said, a person drove his car into the parking lot and the two youths got into their car and drove away.

The undercover officers followed in three cars and surrounded the car when it stopped at a nearby traffic light on Georgia Avenue, Geehreng said. As Arnold approached the front of the car on foot, Geehring said, the driver put the car in a forward gear and jumped out.

The 16-year-old was arrested at the scene. Arnold shot at the 17-year-old with his shotgun, Geehreng said, but it remained unclear how many shots were fired or whether any other officers fired. Geehreng said the incident was being investigated by the police internal affairs division.

Both youths were charged with attempted robbery, assault with intent to murder and with auto theft. Police said the car they were driving had been reported stolen in Northwest Washington at about 9 p.m. on Sunday.