WASHINGTON, Aug 27: Forty-nine people were killed in southern United States on Sunday when a passenger plane crashed shortly after the take-off.

Federal aviation authorities told reporters that 50 people –- 47 passengers and three crew – were on board when the plane take-off from the Blue Grass Airport in Lexington, Kentucky.

The airport’s Executive Director Michael Gobb said the aircraft experienced difficulty on departure and crashed about two kilometres from the runway. He said one crash victim was taken to a hospital.

A witness said he heard an explosion early and saw a bright light near the airport at the time of the crash. The 50-seat commuter plane — a Bombardier Canadian Regional Jet (CRJ) 100 — was operated by Delta’s commuter carrier, Comair.

Weather conditions were about normal at the time of the crash, officials noted. In the past few days there had been several thunderstorms in the area, but by Sunday the weather had settled down.

There was no immediate word on what caused the crash but terrorism has been ruled out. “We have no indication at all that this has anything to do with terrorism,” said Laura Brown, a spokeswoman for the Federal Aviation Authority.

The plane was largely intact afterward, but there was a fire following the impact, police said.

The crash marks the end of what has been called the “safest period in aviation history” in the United States.