4 Russian subway stations closed after bomb threat

Four subway stations in St. Petersburg are closed following a bomb threat, the day after a bomb killed 14 people and wounded dozens.The Sennaya Square station in the city center was cordoned off on Tuesday, and commuters were told via a PA announcement that three more stations have also been closed down.A bomb went off on a subway train under Russia's second-largest city on Monday. A second device was found and deactivated.An explosion on a moving train near the same station killed 14 people on