In the video, the bomber approaches the train station looking like any normal traveller, enters the front door, gets to the metal detector, and detonates.
The explosion was the first of two in one day; later, another suicide bomber struck a trolley, killing 14 people.
Business Insider contributor and Russia security expert, Mark Galeotti writes, “It is hardly a coincidence that as Sochi nears, so does the tempo of attacks outside the North Caucasus region itself: the Volgograd bus bombing in October, Friday’s car bomb in Pyatigorsk, now this.”
Security experts have made it no secret that they are worried about the Winter Olympics in Sochi.
And it seems like there’s almost nothing security teams can do to avoid attacks like this.
Watch [WARNING, violent explosion occurs]:
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