Members of the emergency services work at the site of a bomb blast on a trolleybus in Volgograd December 30, 2013 (Photo: Reuters)
Members of the emergency services work at the site of a bomb blast on a trolleybus in Volgograd December 30, 2013 (Photo: Reuters)
Members of the emergency services work at the site of a bomb blast on a trolleybus in Volgograd December 30, 2013 (Photo: Reuters)
Ambulances line up a site of a trolleybus explosion, background, in Volgograd, Russia Monday, Dec. 30, 2013 (Photo: AP)
Members of the emergency services work at the site of a blast on a trolleybus in Volgograd in this December 30, 2013 (Photo: Reuters)
A Volgograd resident walks crying in Volgograd, Russia early Monday, Dec. 30, 2013 (Photo: AP)
Police officers with a sniffing dog examine territory around the site of a trolleybus explosion in Volgograd, Russia, Monday, Dec. 30, 2013 (Photo: AP)
In this photo made by a public camera and made available by the Associated Press Television News the flash of an explosion illuminates the entrance to Volgograd railway station in Volgograd Russia on Sunday, Dec. 29, 2013 (Photo: AP)
Investigators work at the site of an explosion at the entrance of a train station in Volgograd December 29, 2013 (Photo: Reuters)