An explosion rocked the subway system of Russia's second largest city, St. Petersburg. According to preliminary reports, ten people were killed in the incident. The incident occurred at about 14:40 Moscow time, when an unidentified explosive device went off in a subway car as it was travelling between the Tekhnologichesky Institut and Sennaya Ploshchad stations on the blue line of St. Petersburg’s metro. About 50 people were hurt in the blast, spokesman for the city’s governor Andrei Kibitov said.