Three people may have been killed and dozens injured as several subway cars derailed on the Moscow Metro on the Arbatsko-Pokrovskaya dark blue Metro line on Tuesday morning, RT reported.
"According to preliminary reports, the fourth subway train car derailed 200 meters away from Slavyansky Bulvar Metro station," a source in Moscow law enforcement agencies told ITAR-TASS.
A law enforcement official later told ITAR-TASS that not one, but three train cars had derailed, "but not overturned." The same source said 50 people could have been injured.
About 20 people remain trapped in one of the train carriages, according to RIA Novosti, citing a source with the Moscow Police.
Attempts are being made to try and evacuate the stricken passangers, who are stuck in a tunnel between Park Pobedy and Slavyansky Bulvar stations, in the west of Moscow.
There are some seriously injured people, according to preliminary reports. Doctors and rescue workers have deployed stretchers down the tunnel for their evacuation.
News of the derailment was preceded by reports of smoke detected on the dark blue line of the Moscow Metro. Later, Moscow's emergencies agency denied reports of smoke and said a sudden failure in the electricity supply to a conductor rail could have caused the accident.