Deadly blast at Russia's Volgograd station
29 December 2013 Last updated at 18:10 GMT
An explosion at a train station in the southern Russian city of Volgograd has killed at least 15 people, according to reports.
A female suicide bomber was thought to be responsible for the blast, Russia's anti-terrorism committee said.
Moscow is concerned militant groups could be ramping up violence in the run up to the the 2014 winter Olympic Games in Sochi.
Daniel Sandford reports.