The state flag is at half mast throughout the country and entertainment events and programmes have been cancelled.
The Russian Government and the regional authorities have been instructed to provide the necessary assistance to the families of the victims.
President Vladimir Putin signed the decree declaring a day of mourning on July 9.
Mr Putin expressed his profound condolences to the families of the victims.
On the President’s instructions, a government commission headed by Transport Minister Igor Levitin has been formed to investigate the causes of the crash of the A-310 aircraft in Irkutsk.