Two explosions have reportedly occurred in separate stations of the Metro system of St. Petersburg, Russia, resulting in at least 10 people being killed and about 20 others injured. One blast, at the Sennaya Ploshchad station, went off inside a train car, blowing out one of its doors. The other occurred at the Tekhnologichesky Institute station. Both are thought to have been caused by IEDs containing shrapnel. Several Metro stations have been closed, with people being evacuated.
Read more at Sputnik International, Russia Today, The Guardian, The Telegraph and the Independent.
UPDATE: The linked articles now indicate that the report of two bombs was incorrect. Instead, a single blast occurred along the Metro's Blue Line between the two above-mentioned stations. A second device was found in another part of the Metro, but it had not detonated.
UPDATE 2: The number of dead is now reported to be 11, with 45 others injured.