Most likely, the craft started to collapse at a considerable altitude-most likely, with the passenger cabin depressurized. The jet struck the ground in pieces. No traces of fire have been found, says Rudolf Chernenko, Rostov airport search-and-rescue chief.
Search is on within a 25 kilometer radius, and the area will extend if not all bodies are recovered on the site, he added to a media audience.
There were 42 to 46 on board, says specified information. Initial reports referred to 46, including a crew of eight, the regional board of the Emergencies Ministry said to Novosti.
Twenty bodies have been recovered for now.
The Sochi-bound Tu 154, of Sibir Airlines, started from Moscow's Domodedovo airport, Flight 1047. It crashed near Kamensk, 138 kilometers off Rostov-on-Don, 10:35 p.m., Moscow time, August 24.
