Details added, first version posted at 14:16
The death toll from an explosion at a train station in Russia's southern city Volgograd on Sunday continues to rise, with over a dozen people killed and scores more injured in what officials said was likely an attack by a female suicide bomber, RIA Novosti reported.
Police said that at least 18 people were killed and over 40 more injured by the blast that took place at 12:45 p.m. (8:45 a.m. GMT) in the Volgograd-1 train station.
Russia's Investigative Committee said the number of casualties from the explosion, which it called a terrorist attack, was at least 13.
Victims of the blast are being evacuated by Russia's Emergency Situations Ministry by plane to Moscow, approximately a 90-minute flight away, for medical help.
The head of the region's Interior Ministry Svetlana Smolyaninova told RIA Novosti that the explosion happened on the second floor of the train station, though other sources in local law enforcement said it went off on the ground floor of the building ahead of the metal detectors.
The National Anti-Terrorism Committee said that the explosion was caused by an unidentified device and that it was probably the work of a female suicide bomber, though it did not speculate on who might be responsible in the statement.
Police initially reported three people dead and six injured, but later revised the number of victims upward. Oleg Salagai, a spokesman for Russia's Health Ministry, said on the Rossiya-24 television channel that at least 50 people had been injured by the explosion, and that dozens of emergency medical teams were working to assist the victims.
Long-distance trains at the main part of the station are still running on schedule despite the explosion, a Russian Railways representative told RIA Novosti.
Volgograd was also the location of a terrorist attack that killed 6 people and injured 37 more in October, when a female suicide bomber from Russia's southern republic of Dagestan detonated a bus.