The Tupolev-154 was flying from the Russian Black Sea holiday resort of Anapa to St Petersburg.
It crashed about 45km (30 miles) north of the city of Donetsk in eastern Ukraine.
The crew of the Pulkovo Airlines flight sent a distress signal just minutes before the plane went down.
The Russian airliner was carrying 160 passengers and 10 crew members.
Local residents gathered to watch rescue workers tackle the flames and billowing smoke.