Butner, N.C. — Both lanes of southbound Interstate 85 near the Durham-Granville County line are shut down after an accident involving three tractor-trailers.

Authorities said the accident occurred at 9:55 a.m. Friday at mile marker 186 near Butner. When authorities arrived at the scene, two of the tractor-trailers were on fire. Troopers believe two of the tractor-trailers were parked on the shoulder of southbound I-85 when both were struck by the other tractor-trailer, causing an explosion.

According to witnesses, a man and a woman were pulled from one of the tractor-trailers and appeared to be OK. Witnesses also said several drivers, including a doctor from Georgetown University Medical Center, stopped to assist those involved in the accident.

The Highway Patrol confirms that there are two fatalities, but their names have not yet been released. There are also reports of some people being badly burned, but it is not known how many. A Duke Life Flight helicopter transported some of the injured from the scene.

Hazmat crews determined that there were not any hazardous materials on the tractor-trailers. The Highway Patrol is going through the wreckage in hopes of finding out more about the accident.

Traffic is backed up for miles and the roadway is expected to reopen sometime Friday afternoon. Motorists are being urged to detour onto Central Avenue (exit 189) and then onto U.S. Highway 15 south back to I-85.

Stay tuned to WRAL.com and WRAL-TV for the latest details with this developing story.