An Atlasjet plane crashed shortly before it was to land in central Turkey early today, killing all 56 people on board, the airline's chief executive said.

A rescue helicopter had reached the wreckage of the plane on a mountainous region near the town of Keciborlu in Isparta Province and reported back that no one had survived the crash, airline CEO Tuncay Doganer said.

The MD 83 jetliner took off from Istanbul at 1:55 a.m. local time, headed to Isparta but went off the radar just before landing.

Doganer said the cause of the crash was not known. But he ruled out weather conditions, saying there was no fog or strong winds at the time of the crash.

Families of the passengers first rushed to the airports of Istanbul and Isparta for news of their loved ones and later began heading toward the crash scene, private NTV television reported.