At least 15 people were killed on Sunday when a suspected female suicide bomber detonated an explosive device inside a train station in Volgograd, Russia.

Russia Today, a government-funded, English-language news outlet, reports that authorities are treating the incident as a terrorist attack. RT adds:

"'According to preliminary reports, this was a terrorist act. Fifteen people have lost their lives, 37 were injured, 30 of them more critically than others. An Emergencies plane is waiting to be dispatched from Moscow,' Volgograd Region governor Sergey Bozhenov told ITAR-TASS.

"However, the Health Ministry confirms that 27 people have been taken to hospital. According to the Investigative Committee, a child of 9 was among the injured."

NBC News reports this is the second deadly attack in three days and it comes just as Russia is getting ready to host the Winter Olympics.

"On Friday, a car bomb killed three people in the southern Russian city of Pyatigorsk, 170 miles east of Sochi," NBC reports. "In October, another female suicide bomber was blamed for a bus explosion in Volgograd that killed five people."

The AP reports that security cameras show that the suicide bomber detonated the device as she was preparing to pass through a metal detector.

There was no immediate claim of responsibility, but the attack comes after Chechen rebel leader Doku Umarov called for new attacks against civilians that would disrupt the Games.

Update at 9:12 a.m. ET. Video Of The Blast:

The Russian newspaper Gazeta has posted video from the moment of the blast. It is stunning:

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