At least 10 people have died and scores more have been injured after a rush-hour subway train derailed in Moscow Tuesday, health officials said.
Some 106 people were hospitalized, of whom 50 are in grave condition, Russian news agency ITAR-TASS said, quoting Moscow's health department chief, Georgy Golukhov.
The crash is said to have occurred after several cars left a track in a tunnel after a power surge triggered an alarm.
Photos on social media showed passengers walking along the tracks inside the dimly lit tunnel.
There have been 13 emergency incidents on Moscow's metro system so far this year but no one was injured in the earlier incidents, according to ITAR-TASS.
Moscow's metro system is one of the world's oldest and most extensive.