Photos showed the Crocus City Music Hall engulfed in flames as videos emerged from the concert hall attack, showing at least four gunmen opening fire from automatic weapons as panicked Russians fled for their lives.

In one video, three men in fatigues carrying rifles fired at point blank range into bodies strewn about the lobby of the concert hall.

The attackers also apparently detonated explosives, as the the sounds of blasts could be heard in other videos from the attack.

Moscow mayor Sergei Sobyanin called the attack a “great tragedy".

At least 50 ambulances had been dispatched to the site of the attack.