Leonid Kastorsky, the head of the regional office of the Ukrainian Emergency Situations Ministry, said "it is already known for certain at this time that there are no survivors. Emergency units that arrived 10 minutes after the plane crash managed to extinguish the fire. However, nobody could be rescued."
A spokeswoman for Ukraine's Emergency Situations Ministry, Tetyana Litvinova, told RFE/RL's Ukrainian Service that there were 160 passengers and 10 crew members on board.
Vasily Nalyotenko, deputy head of Pulkovo Airlines, the company that operated the plane, says the dead include 39 children.
Pulkovo is one of Russia's largest carriers.
Ukraine's Emergency Situations Ministry says the pilots of the plane, a Soviet-designed TU-154, had reported a fire inside the plane as it cruised at an altitude of some 10,000 meters.
Russia's Emergency Situations Ministry says a lightning strike may have caused the crash.
The plane was en route from the southern Russian resort of Anapa to St. Petersburg.