>> The force of the explosion was instantly clear. A set of doors replaced by twisted metal and a gaping hole. As survivors hammer on the windows of the train to help anyone trapped inside. At least ten people were killed in the explosion on the Saint Petersburg Metro, at least 20 more injured, in what authorities have called a probable terrorist attack.
Reuters Moscow Bureau Chief, Christian Lowe.>> There's no indication yet of who it is. What we can talk about is who's been responsible for similar attacks in the past in Russia. And in that case, we can say that there have been numerous attacks of this nature on public transport in Russian cities.
And the people behind those have been Islamist rebels, many from the North Caucasus. Russia's Interfax news agency said the blast may have been caused by a device concealed in a briefcase. Police are reportedly searching for the man caught on CCTV. It happened in the early afternoon at the Sennaya Plosched station near the center of Russia's old imperial capital.
Emergency services swarmed the road above, Including a helicopter landing just meters from parked cars, and an endless stream of fire crews, and ambulances, to treat the wounded. Initial reports were of two explosions. It was later confirmed to be one, but Russian investigators said another explosive device was discovered and diffused at a separate station.
Russian president Vladimir Putin was in the city at the time meeting the leader of Belarus. His response so far has been cautious.>> The Kremlin is very keen not to do anything that would trigger certain people, Russian citizens, to go out into the streets and attack their Muslim neighbors.
There are millions of Muslims in this country. And the Kremlin is very keen to preserve harmony between these different communities.>> Investigators have said, they will consider all possible causes. Russia has been the target of attacks by Chechen separatists in the past. Islamic state has also a threatened attacks in retaliation for Russian military intervention in Syria.