By: (MEE)   At least nine people were killed and 20 injured in explosions in a train carriage at metro stations in St Petersburg on Monday, Russia's national anti-terrorist committee said.

Interfax news agency quoted an unnamed source as saying the blast was caused by a bomb filled with shrapnel. Another source in Russia's emergency services told Reuters there had been only one bomb blast.

"There was one blast in one site in between (stations) as the train arrived at the Technology Institute station from Sennaya (Ploshchad) station," the source said.

Russian media reported earlier that there were two blasts and that at least 10 people had died.
President Vladimir Putin, who was in St Petersburg for a meeting with Belarussian leader Alexander Lukashenko, said the cause of the blasts was not yet clear and efforts were under way to find out. He said he was considering all possibilities including terrorism.

No individual or group has claimed the apparent attack.

Video showed injured people lying bleeding on a platform, some being treated by emergency services. Others ran away from the platform amid clouds of smoke.

A huge hole was blasted in the side of one carriage with mangled metal wreckage strewn around the platform. Passengers were seen hammering at the windows of one closed carriage.

Authorities closed all St Petersburg metro stations. The Moscow metro said it was taking unspecified additional security measures in case of an attack there.