At least 31 people killed in two bombings in RussiaUpdated: 2013-12-30 PM 10:47:24 (KST)
Russia's city of Volgograd is in fear.
Two suicide bombings in less than 24 hours have killed at least 31 people and injured more than 60.
Security had been stepped up at train stations and airports around Russia after a suspected female suicide bomber attacked Volgograd's main train station on Sunday, killing 17 people.
And then, with the shock of that bomb attack still fresh, a second deadly blast hit the city on Monday morning local time, killing at least 14 people and wounding scores more.
Federal investigators are calling Monday's explosion on a trolleybus a "terrorist act."
They believe a male suicide bomber was responsible, and there are strong indications that the incident is linked to Sunday's bombing.
Journalists in the area reported the roof of the trolleybus was blown off, with debris and bodies being scattered on the streets.
Several windows in the vicinity broke.
As for Sunday's bombing, Russian authorities are still investigating, but they say the bomber detonated explosives in front of a metal detector just inside the main entrance of the station that was bustling with holiday travelers.
"According to our information, a female suicide bomber approached the metal detector, saw policeman there, got nervous and detonated the bomb. It could've been worse if the bomber passed through into the waiting hall, as the explosion was the equivalent of 10 kilograms of TNT."
While the bomber's identity has still to be confirmed, female suicide bombers known as "black widows" - the family members of dead insurgents - have carried out a number of attacks in nearby Muslim regions that stand opposed to the Russian government.
Volgograd is located less than a thousand kilometers northeast of Sochi, the host city for the Winter Olympics.
The two consecutive attacks are raising security concerns, with the event kicking off in just six weeks.
Kwon Soa, Arirang News.
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