A Malaysian passenger airliner with 295 people on board crashed in Ukraine near the Russian border on Thursday, the Interfax news agency cited an aviation industry source as saying.
The Boeing plane was flying from Amsterdam to Kuala Lumpur, it said. Reuters could not immediately confirm the report.
The Interfax report said the plane came down 50 km (20 miles) short of entering Russian airspace. It "began to drop, afterwards it was found burning on the ground on Ukrainian territory," the unnamed source said.
The plane appeared to have come down in a region of military action where Ukrainian government forces are battling pro-Russian separatists.
A separate unnamed source in the Ukrainian security apparatus, quoted by Interfax, said the plane disappeared from radar at a height of 10,000 meters after which it came down near the town of Shakhtyorsk.