Officials say there are no known injuries; assistant fire chief says gas now off

Minneapolis - Officials said a fiery blast in south Minneapolis Thursday morning was a natural gas line explosion and that there are no known injuries.

Assistant Fire Chief Cherie Penn said people are still being evacuated from the area, but he described the evacuations as precautionary.

TV reports showed flames shooting high into the air near the interchange of Interstate 35W and Highway 62, at 60th Street and Nicollet Avenue.

Video shot near the explosion reveals the size - and heat - of the towering fireball. Narrating as he drives by at a safe distance, Twitter user Robert Stephens said, "from about two blocks away I can feel the heat on my face, and as it got closer, you can hear the hissing sound."

The video also purports to show flames shooting up from the street.

The blast happened Thursday morning in front of a Cub Foods store in an area that is a mix of residential and industrial. According to affiliate KARE, an emergency response team is evaluating the situation.

Minnesota Department of Transportation spokesman Kevin Gutknecht said the fire was not on Interstate 35W, but the department closed the southbound lanes of the interstate just north of the Highway 62 because the blaze was a distraction to drivers. He said the flames are not blowing over the roadway.

MSNBC and AP affiliate KARE contributed to this report.