Large fire collapses portion of Atlanta highway, causing heavy traffic delays

— -- A massive fire on Interstate 85 in Atlanta that caused major traffic delays Thursday after a portion of the highway collapsed has prompted Georgia governor Nathan Deal to declare a state of emergency for Fulton County.

"The state is mobilizing all available resources to ensure public safety and minimize disruption of traffic as we continue emergency response efforts," Deal said in a statement. "As this safety investigation and bridge assessment continues, we encourage the public to avoid the affected area, remain patient and allow first responders to perform their jobs. We will continue updating the public on alternative traffic routes and other information as it becomes available.”

Video from ABC Atlanta affiliate WSB-TV shows the fire that broke out in an industrial area near route 400. Traffic was halted as firefighters attempted to extinguish the blaze.

At a press conference Thursday night, Atlanta mayor Kasim Reed said there is no evidence that this incident is terror-related.

He added that it could take between 4 and 8 weeks to repair the highway.

Black smoke billowing from the flames could be seen for several miles away and was posted to social media by commuters in the Atlanta metro area.

It is unclear how the fire started. Witnesses told WSB-TV that Atlanta state troopers were telling cars to turn around on the bridge minutes before it collapsed because they were concerned about its integrity. All of the firefighters were able to get out of the area prior to the collapse, according to WSB-TV.

Officials said on Thursday evening that the fire has been brought under control and that there were no reports of any injuries in the blaze.

ABC News' Benjamin Stein contributed to this report.