About 10 people have been killed in an explosion between two underground stations in St Petersburg.
The head of Russia’s National Anti-Terrorist Committee said the blast hit the train between Sennaya Ploschad and Tekhnologichesky Institut stations. Images posted on social media showed a badly mangled carriage, with a number of casualties nearby.
President Vladimir Putin said all causes, including terrorism, were being investigated.
Initial reports suggested there had been two explosions, one at each of the two stations. A spokesman for St Petersburg’s governor said at least 10 people had been killed and 50 injured. But minutes later, Russian National Anti-Terrorist Committee said the death toll was nine, with 20 hurt.
Andrei Przhezdomsky, the head of the committee, said the explosion at 14:40 local time (12:40 BST) was caused by “an unidentified explosive device” but that the exact cause had yet to be determined.