"The plane landed at 10:22 a.m. local time", the source said, adding that according to preliminary data, an alarm about the aircraft's fire entinguishing system malfunctioning went off during the flight.
The day before, Russian Prosecutor General Yury Chayka slammed the Russian Federal Air Transport Agency for often failing to ensure sufficient control over aviation companies' activities.
According to the official, since 2017, 550 pilots were put on suspension and 160 flight certificates were annulled in Russia as a result of prosecutors' investigations.
The accident left 41 out of the 78 people on board killed. The pilots' potential inexperience has been put forward as one of the possible causes of the tragedy.