At least 10 people have been killed and several injured in a blast in the St Petersburg metro on Monday.
There were explosions in two train carriages at two metro stations, St Petersburg emergency services said.
“An evacuation from the stations is ongoing, there are people injured,” the Saint Petersburg metro said in a statement carried by Russian news agencies. “An unidentified object supposedly blew up in a (train) carriage.”
Social media users posted photographs from one subway station in the city centre, showing people lying on the floor and a train with a mangled door nearby.
A Reuters witness saw eight ambulances near the Sennaya Ploshchad metro station.
Russian news agencies quoted Kremlin spokesman Dmitry Peskov saying that Russian President Vladimir Putin has been informed about the explosion.