Russian authorities have begun investigating the cause of the deadly subway derailment in Moscow.
3 cars of a subway train derailed near Slavyansky Boulevard Station on Tuesday morning. The first car was severely damaged.
The emergency ministry says at least 21 people died and about 130 have been hospitalized for injuries.
Investigators say the derailment may have been caused by problems with the switching gear, the track bed or the train itself.
They say the train was packed with commuters at the time of the accident, and many passengers were thrown from their seats.
In March 2010, dozens of people were killed in terrorist bombings on the Moscow subway. Tuesday's derailment is the first major subway accident since the collapse of the Soviet Union.
Jul. 15, 2014 - Updated 22:37 UTC