At least 16 people have been killed in a bomb explosion at a Russian train station, the second deadly attack in the space of three days as the country prepares to host the Winter Olympics.
The state Investigative Committee said a suicide bomber detonated the explosives in front of a metal detector just inside the main entrance of Volgograd station.
Footage shown on TV showed a massive orange fireball filling the hall and smoke billowing out through shattered windows.