Explosion on St. Petersburg subway in Russia injures several

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) (The Associated Press)

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) (The Associated Press)

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) (The Associated Press)

The subway in the Russian city of St. Petersburg is reporting that several people have been injured in an explosion on a subway train.

The subway's administration says several stations in the northern Russian city have been closed and that an evacuation is underway Monday afternoon.

Social media users posted photographs from one subway station in the city center, showing people lying on the floor and a train with a mangled door nearby.

Russian news agencies quoted Kremlin spokesman Dmitry Peskov saying that Russian President Vladimir Putin has been informed about the explosion. Putin is visiting the city Monday and is expected to hold talks with the Belarusian president later in the day.