Officials says Sunday and Monday's attacks may be evidence that militants are using the city of Volgograd as a transportation hub.
Alphonso Van Marsh, of CBS News reports, a suicide bomber shredded a bus in the Russian city of Volgograd. The second attack in as many days.
Russian officials say the attack killed or injured dozens of people. Now there's fear of more terrorism, ahead of February's Winter Olympics in Sochi, about 400 miles away. Investigators say the bomber's explosives were similar to those used in another suicide bombing on Sunday at the city's main railway station. Atleast 17 people died there.
It is unclear who carried out the attacks. In July, Chechen militants calling for an Islamic State in Russia, threatened to attack civilian targets, including the Olympics. The double suicide bombings have security experts concerned
Officials says Sunday and Monday's attacks may be evidence that militants are using the city of Volgograd as a transportation hub to show their reach outside of the bases in Russia's Caucasus region
Russian President Vladimir Putin is ordering increased security nationwide. The International Olympic Committee says it is confident of Russia's ability to keep the Games safe.