Some witnesses told state channel Rossiya-24 they saw a man thrown from the plane as it rammed into the barrier of the highway outside Vnukovo airport, just southwest of the capital, and another described pulling other people from the wreckage.
"The plane split into three pieces," Yelena Krylova, chief spokeswoman for the airport, said in televised comments.
Police spokesman Gennady Bogachyov said: "The plane went off the runway, broke through the barrier, and caught fire."
The pilot, co-pilot, flight engineer, and a flight attendant were killed and the other four crew members aboard – all flight attendants – were in a serious condition in the hospital with head injuries, the Emergency Situations Ministry said.
Officials said earlier that there were 12 crew on board.