A Turkish airliner crashed near the town of Isparta in central Turkey on Friday, killing all 56 people on board, officials said.

"Rescue teams have reached the wreckage ... There are no survivors," the chief executive of the AtlasJet airline, Tuncay Doganer, told a televised news conference. Officials said all on board appeared to have been Turkish.

The 165-seat MD 83 plane, manufactured by McDonnell Douglas, crashed in the early hours of Friday in mountains in the Isparta province of central Turkey. It had been flying from Istanbul with 49 passengers and seven crew.

It was not immediately clear what had caused the crash, which occurred 12 km (7.5 miles) from Isparta's Suleyman Demirel airport.

Doganer said weather conditions were not abnormal at the time of the crash and that he knew of no technical deficiencies aboard the aircraft. The aircraft's black box should explain what happened, he said.

Turkey is now in the grip of winter with snow and fog common on higher ground across much of the country.

Rescue workers reached the mountainous crash site after military helicopters spotted the wreckage of the airliner.

Turkish television showed anxious relatives arriving at Istanbul airport seeking news about the passengers.

The aircraft disappeared from radar screens shortly before it was due to land at Isparta, about 150 km (90 miles) north of the Mediterranean resort of Antalya.

The state Anatolian news agency said aviation authorities lost contact with the plane just after the pilot said he was preparing to land at Isparta.

"As the plane was approaching its descent, it sought permission to land and after receiving a positive reply from the tower contact was lost," the agency quoted local deputy governor Tayyar Sasmaz as saying. -Reuters