People watch the flames shoot up from a freight train that derailed and some cars burst into flames, early Wednesday morning July 11, 2012 in Columbus Ohio. (AP Photo/Andrew Spear)

COLUMBUS, Ohio (AP) — A freight train derailment and explosion in Columbus, Ohio, has authorities evacuating a mile-wide area of the city as they try to contain the blaze and determine what's burning.

Norfolk Southern says it appears about 11 cars of a southbound train derailed around 2 a.m. Wednesday near Interstate 71, southeast of the Ohio State University campus. It wasn't immediately clear what caused the crash, how many cars caught fire or what they contained.

A photographer who was in the area says he was more than 10 miles away in New Albany when he saw something illuminate the sky. He says he went to the scene to take photos and noticed a chemical smell in addition to the smoke.

A fire official says two people were injured, but no details were available.