The Russian national flag (L) and the flag of St. Petersburg fly at half-mast on top of St. Petersburg's Legislative Assembly in tribute to the victims of a blast in St.Petersburg metro, in St. Petersburg, Russia, on April 4, 2017. The bombing in the subway system in St. Petersburg on Monday has killed 14 people, Russian Health Minister Veronika Skvortsova said Tuesday. (Xinhua/Lu Jinbo)
