Russian security tightens as Olympics approach
Russian policeman Vladislav and Lora, a german shepherd sniffer dog, stand guard in front Sochi's airport in Adler, Jan. 15, 2014.
Read more: Security threats at Sochi Olympics worry U.S. officials
Sochi
A Russian traffic police officer patrols a road near venues at the Olympic Park near Sochi, Jan. 7, 2014.
Russian forces went on combat alert in Sochi and tightened restrictions on access to the Black Sea resort as part of measures by President Vladimir Putin to ensure security at next month's Winter Olympics.
Volgograd
Russian Cossacks, who started regular patrols within the city in the wake of recent suicide attacks, board a trolley bus while patrolling the streets in the southern Russian city of Volgograd, Jan. 4, 2014.
According to local media, over 400 Cossacks arrived at Sochi on January 9 to provide security for athletes, foreign delegations and tourists.
Cossacks, the descendants of settlers in Southern Russia and Siberia, help maintain law and order in Russian cities by assisting local police in patrols and checking of identification documents and luggage.