A recent wave of violence in Russia, including bombings in Volgograd on Dec. 29 and Dec. 30 (above), have stoked fears of a terror attack at the Winter Olympics in Sochi next month. (AP Photo/Denis Tyrin, File)

A recent wave of violence in Russia, including bombings in Volgograd on Dec. 29 and Dec. 30 (above), have stoked fears of a terror attack at the Winter Olympics in Sochi next month. (AP Photo/Denis Tyrin, File)