A Look Inside Russia Subway Station Following Derailment

PHOTO: One of the passengers injured as several subway cars derailed in Moscow, July 15, 2014, speaks by his cell phone after being rescued and treated by paramedics. PlayDmitry Serebryakov/AFP/Getty Images
WATCH At Least 20 Dead in Moscow Subway Train Derailment

A rush-hour subway train derailed in Moscow today, killing at least 20 people and injuring more than 160 others, authorities said.

Several cars left the track in the tunnel after a power surge triggered an alarm, which caused the train to stop abruptly.

PHOTO: Smoke and twisted metal was visible following a subway train derailment in Moscow, Russia, July 15, 2014.RU-RTR
Smoke and twisted metal was visible following a subway train derailment in Moscow, Russia, July 15, 2014.

The scene was chaotic, featuring cars piled upon other cars, twisted metal and smoke. More than 1,100 people were evacuated from the tunnel where the derailment occurred.

PHOTO: Some passengers remained trapped for hours following a train derailment in Moscow, July 15, 2014.RU-RTR
Some passengers remained trapped for hours following a train derailment in Moscow, July 15, 2014.

The station where the crash occurred is one of the deepest in the subway system, making rescue efforts more challenging.

PHOTO: Rescue workers carry an injured passenger up the steps following train derailment in Moscow, Russia, July 15, 2014.APTN
Rescue workers carry an injured passenger up the steps following train derailment in Moscow, Russia, July 15, 2014.

Emergency crews could be seen carrying injured travelers on stretchers up the subway steps, loading them into ambulances and helicopters.

PHOTO: Emergency crews carry an injured passenger out from a subway station after a train derailment in Moscow, July 15, 2014.APTN
Emergency crews carry an injured passenger out from a subway station after a train derailment in Moscow, July 15, 2014.

Some passengers remained trapped hours after the derailment.

PHOTO: Paramedics, a police officer and a volunteer carry an injured man out from a subway station after a rush-hour subway train derailment in Moscow, Russia, July 15, 2014.Ivan Sekretarev/AP Photo
Paramedics, a police officer and a volunteer carry an injured man out from a subway station after a rush-hour subway train derailment in Moscow, Russia, July 15, 2014.

Wednesday has been declared a day of mourning in Moscow.

PHOTO: Paramedics carry an injured woman out from a subway station after a rush-hour subway train derailment, to be transported by a medical helicopter in Moscow, Russia, on Tuesday, July 15, 2014.Ivan Sekretarev/AP Photo
Paramedics carry an injured woman out from a subway station after a rush-hour subway train derailment, to be transported by a medical helicopter in Moscow, Russia, on Tuesday, July 15, 2014.

There are no reports of terrorism, authorities said.

PHOTO: Rescuers run to evacuate the passengers as several subway cars derailed in Moscow, July 15, 2014. Dmitry Serebryakov/AFP/Getty Images
Rescuers run to evacuate the passengers as several subway cars derailed in Moscow, July 15, 2014.

The Associated Press contributed to this report.