Amsterdam - Speculation about the cause of the Turkish Airlines crash near Schiphol Airport that left 9 people dead and 86 injured on Wednesday, continued Thursday while investigators were still studying the accident.

Thirty of the injured remained hospitalized, with six people still in critical condition.

Information about the passenger list was not yet released to the media.

Schiphol Airport's disaster team spokesman said "discrepancies" between the lists provided by the airline and the list drafted by Dutch authorities had not yet been resolved.

He added more information might come from the next press conference set at 1200 GMT.

Investigators of the Dutch Safety Board, which investigates all major accidents in the Netherlands, were at the crash scene Thursday studying the wreckage of the Boeing
737 plane.

The airplane will remain at the site for further investigation expected to last at least until Sunday.

Air traffic on the Polderbaan runway where the plane was to have landed will not be resumed until the aircraft's wreckage has been removed, airport officials said.

Meanwhile speculation about the cause of the crash continued, fed by reports from eyewitnesses on the ground.

Several people told Dutch media their attention was initially drawn to the plane because they first heard it flying unusually low and making relatively much noise, following which all sound died away.

Speaking in a late night current affairs show on Dutch television, Hans Tettero of the Dutch pilots association said this might indicate a complete and sudden failure of both engines.

He added this could have had several reasons, including possible human error, a blockage of fuel to the engines, or that the plane simply ran out of fuel, either due to leakage or not enough fuel having been taken on board for the flight.

But Tettero believed that insuffucient fuel intake was not a likely cause because "airlines maintain an absolute minimum of 30 to 45 minutes extra flying time when calculating the required fuel." (dpa)