Durham, N.C. — A Durham police officer was seriously injured Wednesday when a tractor-trailer plowed into her patrol car on Interstate 85 in Durham, police said.

The officer was conducting a traffic stop near the Cole Mill Road exit around 4 p.m. when she was rear-ended, causing her car to spin and clip the vehicle she had pulled over.

She was taken to Duke University Hospital, where she was listed in critical condition Wednesday evening. The officer's name has not been released.

The truck driver and the driver of the stopped vehicle were also hospitalized, but their injuries did not appear to be life-threatening, police said.

Witness Amanda Chavez said the tractor-trailer was swerving before it hit the patrol car.

"She was getting ready to get out and the 18-wheeler was swerving, and he hit her and spun her," she said. "When I got over to the cop car, she was laid over. She wasn't conscious."

About five minutes later, Chavez said, the officer opened her eyes but seemed disoriented.

Chavez described the crash scene as "the worst thing I have seen in my life."

Police released no details about what may have caused the crash or whether the truck driver will be charged.

All southbound lanes of the highway were closed for several hours while authorities conducted their investigation at the scene, which caused major traffic delays in the area.