ST. PETERSBURG, Russia (AP) — The Latest on the explosion on a train in the Russian city of St. Petersburg (all times local):

4:15 p.m.

Russia's National Anti-Terrorism Committee has announced that security will be tightened at all critical transport facilities following St. Petersburg blast.

3:55 p.m.

Andrei Kibitov, spokesman for the St. Petersburg governor, has told Russian television 10 people have been killed and 50 injured in the subway explosion.

In Moscow, Deputy Mayor Maxim Liksutov told the Interfax news agency that Moscow authorities are tightening security on the subway in the Russian capital.

3:45 p.m.

Russian news agencies Tass and Interfax report 10 dead in blast on train in St. Petersburg subway.

Video footage posted on social media website shows a train with mangled doors standing at the platform. Frantic commuters reach out into the doors and windows, trying to see if anyone is there and shouting "Call an ambulance!"

Russian Senator Viktor Ozerov tells Interfax that the explosion looks like a terrorist attack.

3:30 p.m.

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.