St Petersburg Metro bombing as it happened: 11 dead after explosion on underground train network

The investigation into the explosion at St Petersburg Metro is ongoing. See www.ibtimes.co.uk for updates and new stories on the underground attack in Russia.

Authorities are investigating a possible terrorism link. Russia has been targeted by terrorists in the past - most recently in 2015 when Isis claimed responsibility for shooting down a Russian jet over Sinai.

Senior investigator Svetlana Petrenko told Russian media that the train driver's decision to continue to the next station helped save lives, as it meant that rescue workers were able to reach the injured more easily.

A source told Russian news agency Interfax that the suspect who orchestrated the deadly blast may have been captured on the metro's CCTV system.

"Images of the suspected organiser of the metro blast were captured on metro station cameras," the source said.

The explosive device was in a briefcase in a metro carriage, according to Russian news agency Interfax.

The unexploded bomb found at Ploshchad Vosstaniya metro station has been deactivated, according to the anti-terrorist committee.

Russia's anti-terrorism committee has said that nine people have died and 20 have been injured in the explosion.

St Petersburg's Governor Georgy Poltavchenko urged everyone in the city to "be alert, attentive and cautious and to behave in a responsible manner in light of the events."

British Foreign Secretary Boris Johnson has said he is horrified" by the news of the explosion.

This useful map from Russian state media shows how the centre of the city has been effectively sealed off since the attack.

As we have been hearing for some time, the attack in Russia is now officially being called terrorism.

But despite that, attention will surely turn to whether Isis could be behind the attack. Not only did the group threaten attacks in Russia in response to Moscow's backing for Bashar al-Assad in Syria, but there is an active Chechen division within Isis.

Chechen separatists have been fighting a low level insurgency with the Russian state for almost two decades since open warfare between Moscow and Chechnya ended in 1999.

Our colleague over on Newsweek, Jack Moore, speculates that if Isis is indeed behind the bombing, it may not be claimed immediately.

Russian President Vladimir Putin was in a meeting with the President of Belarus, Alexander Lukashenko, in St Petersburg when he was told about the explosion.

He expressed his condolences to the families of those killed and said authorities were investigating whether terrorists set off the explosion.

50 people have been injured in the explosion. The blast ripped apart the train carriages. Emergency workers rushed to the scene to attend to the critically wounded.

President Vladimir Putin has said that authorities are investigating a possible terrorism link.

"The causes of this event have not been determined yet, so it's too early to talk about [possible causes]. The investigation will show. Certainly, we will consider all possibilities: common, criminal, but first of all of a terrorist nature," he said.

Russia national anti-terrorism committee has announced that security will be tightened at critical transport facilities following the blasts.

10 people have been confirmed dead and 50 injured, according to the Russian governor's spokesman.

An unexploded bomb has reportedly been found at a third metro station, Ploshchad Vosstaniya, according to Russian newspaper Novaya Gazeta.

All metro stations have been closed throughout the city.

An eye-witness told Russia's Life news that people were lying bleeding on the ground. "People just fled. My girlfriend was in the next car that exploded. She said that he began to shake. When she came out, she saw that people were mutilated."

Commuters have been evacuated and all metro stations have been closed.