Forty-one people died after a Russian plane made an emergency landing and burst into flames just after takeoff from Moscow's Sheremetyevo airport.
Dramatic video shows passengers using emergency exit slides to escape the burning Aeroflot aircraft.
Survivors suggest the plane was struck by lightning, but Russia's national carrier said only that it returned to the airport for technical reasons.
Two children are among the dead. The jet had 73 passengers and five crew.
Initial reports suggested the plane had landed on fire, but sources quoted by Russian news agency Interfax said the jet caught fire after a very bumpy landing.
The aircraft landed with full fuel tanks because the crew lost contact with air traffic controllers and decided it was too dangerous to dump fuel over Moscow, Interfax added.
"There are 37 survivors - 33 passengers and four members of the crew," said Yelena Markovskaya, an official involved in the investigation of the crash.
A flight attendant was also reportedly killed in the incident. Five people are in hospital. One witness said it was a "miracle" anyone escaped.
What happened to the plane?
The aircraft, a Sukhoi Superjet-100, left the airport at 18:02 local time (15:02 GMT), bound for Murmansk.
Its crew sent a distress signal when "malfunctions" occurred in bad weather shortly after take-off.
After making an emergency landing at the airport, the plane's engines caught fire on the runway, Aeroflot said, adding that the crew "did everything to save the passengers".
One passenger who survived the crash, Petr Egorov, was quoted by the Komsomolskaya Pravda daily newspaper as saying that the flight "had just taken off and the aircraft was hit by lightning", adding: "The landing was rough - I almost passed out from fear."
Aeroflot published a list of survivors (in Russian) who have been identified so far.
Murmansk's Acting Governor Andrey Chibis has reportedly said that the families of those killed in the fire will each receive one million rubles ($15,300; £11,630), while the victims being treated in hospital will be given 500,000 rubles ($7,650; £5,815).
How did the survivors escape?
Mikhail Savchenko claims he was on the plane when it exploded into a fireball on the tarmac but "managed to jump out".
He shared a video of passengers running away from the burning plane, posting: "'Guys I am all right, I am alive and in one piece."
Passengers on board a separate plane awaiting takeoff at the airport posted footage on social media showing fire crews attending the plane on the tarmac.