Putin: Terrorism among causes considered for St. Petersburg Metro blast

All possible causes for the explosion in the St. Petersburg Metro are being considered, including those linked to terrorism, Russian President Vladimir Putin said.

21 dead, scores injured in Moscow metro crash

Twenty-one people died and scores more were hurt after a train derailed in Moscow's packed metro during rush hour on Tuesday in the worst accident to hit one of the world's busiest subways.

Russian television described scenes of chaos and panic on the capital city's famed system, saying passengers fell like dominoes when the train braked abruptly and three carriages derailed.

Rescue teams were combing through the mangled metal carriages in an attempt to extricate several bodies.