At least 10 people were killed in a bomb blast on a subway train in St. Petersburg, Russia on Monday.
Russian media outlets reported the train car explosion injured at least 50 others in what President Vladimir Putin called a possible act of terror.
Investigators are looking into all possible causes of the two separate explosions — one occurring at the Sennaya Ploshad station and the other at the Technological Institute station.
Officials closed all subway stations in the northern Russian city and evacuated passengers. A witness told local press: