In Pics: St Petersburg, Russia, Subway Blast That Killed 10, Injured 50

Emergency services personnel and vehicles are seen at the entrance to Technological Institute metro station in Saint Petersburg on April 3, 2017. Around 10 people were feared dead and dozens injured Monday after an explosion rocked the metro system in Russia's second city Saint Petersburg, according to authorities, who were not ruling out a terror attack. / AFP PHOTO / Olga MALTSEVA

In this image taken from video footage filmed from a moving train on the opposite platform to where the blast occurred, people injured in blast. right, at St. Petersburg's Technological Institute metro station lay on ground, Russia, Monday, April 3, 2017. At least 10 people were killed Monday in an explosion on the subway in St. Petersburg, Russian news agencies reported. (@DARIIIIIINA via AP)

In this grab taken from AP video, Russian police officer, left, and people walk past the damaged train at the Tekhnologichesky Institut subway station in St.Petersburg, Russia, Monday, April 3, 2017. The subway in the Russian city of St. Petersburg is reporting that several people have been injured in an explosion on a subway train. (AP video via AP)

A subway train hit by a explosion stays at the Tekhnologichesky Institut subway station in St.Petersburg, Russia, Monday, April 3, 2017. The subway in the Russian city of St. Petersburg is reporting that several people have been injured in an explosion on a subway train. (AP Photo/www.vk.com/spb_today via AP)

People carrie a subway blast victim into an ambulance after explosion at Tekhnologichesky Institut subway station in St.Petersburg, Russia, Monday, April 3, 2017. The subway in the Russian city of St. Petersburg is reporting that there are fatalities and several people have been injured in an explosion on a subway train. (Alexander Tarasenkov/Interpress via AP)

People carry a subway blast victim into an ambulance after explosion at Tekhnologichesky Institut subway station in St.Petersburg, Russia, Monday, April 3, 2017. The subway in the Russian city of St. Petersburg is reporting that there are fatalities and several people have been injured in an explosion on a subway train. (Alexander Tarasenkov/Interpress via AP)

A helicopter flies over the fire trucks after an explosion at Tekhnologichesky Institut subway station in St.Petersburg, Russia, Monday, April 3, 2017. The subway in the Russian city of St. Petersburg is reporting that there are fatalities and several people have been injured in an explosion on a subway train. (Alexander Tarasenkov/Interpress via AP)

Blast victims lie near a subway train hit by a explosion at the Tekhnologichesky Institut subway station in St.Petersburg, Russia, Monday, April 3, 2017. The subway in the Russian city of St. Petersburg is reporting that several people have been injured in an explosion on a subway train. (AP Photo/DTP&ChP St. Peterburg via AP)

People react outside Technological Institute metro station in Saint Petersburg on April 3, 2017. About ten died and dozens were injured Monday after an explosion rocked the metro system in Russia's second city Saint Petersburg, according to authorities, who were not ruling out a terror attack. / AFP PHOTO / Alexander BULEKOV

People react outside Technological Institute metro station in Saint Petersburg on April 3, 2017. About ten died and dozens were injured Monday after an explosion rocked the metro system in Russia's second city Saint Petersburg, according to authorities, who were not ruling out a terror attack. / AFP PHOTO / Alexander BULEKOV