Sochi: UK officials warn terror attacks 'very likely'
27 January 2014 Last updated at 15:03 GMT
British officials are warning that more terrorist attacks in Russia are "very likely to occur" before and during the Winter Olympic Games in Sochi.
A twin bomb attack in the Russian city of Volgograd in December killed 34 people.
The main threat of terrorist attack is seen as coming from Islamist militants based in the Caucasus Mountains.
Frank Gardner reports.