A Russian plane has crashed in eastern Ukraine minutes after sending a distress signal, killing all 170 people on board, officials said.
Emergency workers battled the flames at the crash scene
The Tupolev-154 was flying from the Russian Black Sea holiday resort of Anapa to St Petersburg when it disappeared from radar screens.
Emergency workers were at the scene of the burning wreckage, about 45km (30 miles) north of the city of Donetsk.
A Russian official said 30 bodies had been found.
The crew of the Pulkovo Airlines flight sent a distress signal at 1537 Moscow time (1137 GMT), and the plane disappeared from radar screens two minutes later, Russian officials said.
An airline official told Itar-Tass news agency that some 40 children were on board.
The plane was carrying 160 passengers and 10 crew.
The fuselage of the plane was entirely destroyed and a thick pall of white smoke hung in the air, an AFP journalist reported from the scene.
"It was falling down like a petal," an unidentified women told Russian television.
"It was floating, it circled around, then it went down. Immediately there was an explosion ... and smoke started rising."
Reports of the cause of the crash were confused. Ukraine's emergencies ministry said a fire had broken out on board, while Russian officials said the accident was probably caused by severe air turbulence.
Ukraine emergencies ministry spokesman Igor Krol said the crew had decided to make an emergency landing after a fire broke out.
Relatives in St Petersburg heard the news of the crash
The plane's landing gear failed to deploy normally and the aircraft crashed "on its belly," Mr Krol told the French news agency AFP.
But Russian officials told the Itar-Tass news agency that the plane had encountered severe weather conditions before it came down.
Irina Andrianova of the Russian emergencies ministry said: "The plane most likely was hit by lightning."
"After it fell, it broke apart and burst into flames," she said in comments on Russian television.
Russia says terrorism has been ruled out as a possible cause.
St Petersburg-based Pulkovo Airlines is one of Russia's larger carriers.
The crash is the third serious air disaster in the region this year.
In July, at least 124 people died when a Russian Airbus A-310 skidded off a runway and burst into flames in Irkutsk in Siberia.