Shocking video captured the moment passengers leapt out of a burning plane and sprinted across tarmac after making an emergency landing.
At least 40 people died when an Aeroflot airliner exploded into a fireball at Moscows Sheremetyevo airport, officials said.
The Sukhoi jet had 73 passengers and five crew members on board when it sped down a runway spewing huge flames and black smoke on Sunday night.
Elena Markovskaya, a spokeswoman for Russias Investigative Committee, said early on Monday that 41 people were killed.
But Health Minister Veronika Skvortsova said later that 38 survived, implying the death toll was 40.
The victims included one member of the crew and at least two teenagers, according to the Investigative Committee.
Video showed desperate passengers leaping out of the plane onto inflatable evacuation slides and staggering across the airports tarmac and grass, some holding luggage.
Another clip, filmed by a passenger inside the plane, captured the moment passengers screamed and fled as flames in the engine spread to the back of the aircraft.
Two children were among the passengers who died, the Investigative Committee said.
At least six people were reported injured.
The airport said in a statement that the plane, which had taken off from Sheremetyevo Airport for the northern city of Murmansk, turned back for unspecified technical reasons and made a hard landing that started the fire.
Some news reports cited sources as saying the plane bounced several times during the landing.
Investigative Committee spokeswoman Svetlana Petrenko said: Investigators soon will begin interviewing victims, eyewitnesses, airport staff and the airline carrier, as well as other persons responsible for the operation of the aircraft.