The Antonov An-148 plane went down in a snow-covered field, making it difficult to access, with emergency workers forced to reach the wreckage by foot or on snowmobiles.
The accident happened in Ramensky district around 70 kilometers southeast of Moscow on Sunday at 2:28 pm after the plane departed from Domodedovo airport outside the Russian capital.
Sixty-five passengers and six crew members were on board and all of them died, Russia's Investigative Committee said.
The flight was operated by the domestic Saratov Airlines and was headed for the city of Orsk in the Orenburg region close to Russia's border with Kazakhstan.
On Monday, rescuers in dark uniforms trudged across the site in formation, using shovels to shift snow around 40 centimeters deep, an AFP video journalist saw.
The Investigative Committee, which takes charge of major incidents and is probing the crash of the 8-year-old plane, said that the aircraft caught fire on the ground after crashing. "At the moment of falling, the aeroplane was intact, without a fire. An explosion took place after the plane crashed," it said, adding that it is looking into factors including the pilots' training and the plane's technical state.
A Swiss citizen and a citizen of Azerbaijan were among the dead listed by the emergency services ministry. A Kazakh citizen may also have died, transport minister Maxim Sokolov said.
Three victims were children, including a 5-year-old girl.
The victims' remains were so damaged that genetic testing is required, investigators said.
Russian President Vladimir Putin sent condolences and "is constantly receiving information" about the crash, his spokesman Dmitry Peskov told journalists.
Putin - who is running for re-election in a March 18 poll - canceled plans to travel to the Black Sea resort of Sochi to meet Palestinian leader Mahmud Abbas on Monday. Instead, the meeting was to take place in Moscow.