A Russian airliner that crashed near a city in the Urals, killing all 88 people on board, caught fire in mid-air, reports say.
The Boeing-737-500, belonging to a branch of the national airline Aeroflot, was on a flight from Moscow to Perm, near the Ural mountains.
Twenty-one foreign passengers were on board the Aeroflot Nord flight.
Radio contact with the plane was lost as it was landing. One witness said it looked like a comet as it came down.
"It looked like a... burning comet. It hit the ground opposite the next house, there was a blaze, like fireworks, it lit the whole sky, the blaze," the witness told Russian TV.
One witness said the blaze lit up the whole sky
The Boeing-737 had 82 passengers on board, including seven children, and six crew, Aeroflot said.
Those killed include Gen Gennady Troshev, a former commander of Russian forces in Chechnya and military advisor to former Russian President Vladimir Putin.
A spokesman for Russian federal prosecutors, Vladimir Markin, said a criminal inquiry had been launched to examine whether safety procedures had been violated.
Earlier, Mr Markin said the most likely cause of the crash was technical failure but Aeroflot says the plane had "a full technical inspection" early this year and was judged to be in a "proper condition".
Aeroflot conducted its own investigation into the causes of the crash and, without giving details, announced it was stripping Aeroflot Nord of the right to use its name from Monday onwards.
Contact with the plane was lost at 0521 Perm time on Sunday (2321 GMT Saturday) as the plane was coming in for landing at a height of 1,100 metres, Aeroflot said.
The minister for security in the region said the plane had caught fire in the air at an altitude of 1,000 metres.
It crashed on the outskirts of Perm, just a few hundred metres from residential buildings, but no one was hurt on the ground.
Part of the Trans-Siberian railway was shut down as a result of damage to the main east-west train track and the blaze took two hours to extinguish.
The 21 foreigners killed were listed as nine people from Azerbaijan, five from Ukraine and one person each from France, Switzerland, Latvia, the United States, Germany, Turkey and Italy, Aeroflot said.
Investigators have recovered two black box recorders from the crash site. There was no immediate suggestion of an attack or sabotage.
Aeroflot's managing director, Valery Okulov, told reporters in Moscow that his company had already conducted its own, private investigation into the crash and decided to sever ties with Aeroflot Nord.
"We have paid too high a price for lending out our flag," he added.
Correspondents say the tragedy will be a setback for Russian aviation, which has been trying to shake off a chequered safety record.
A woman in Perm told Vesti-24 TV how she was thrown out of bed by the force of the blast when the plane crashed.
She said: "My daughter ran in from the next room crying: 'What happened? Has a war begun or what?'
"My neighbours, other witnesses, told me that it was burning in the air."
Sunday's accident was the deadliest involving a Russian airliner since 170 people died in August 2006 when a Tupolev-154 bound for St Petersburg crashed in Ukraine.
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