Follow CBSMIAMI.COM: Facebook | Twitter

MOSCOW (CBSMiami) – Russian President Vladamir Putin said they are considering all possible causes, including terrorism, for an explosion at a rail station in the heart of St. Petersburg.

READ MORE: Surfside Families Push For Permanent Memorial At Site Of Condo Collapse

Interfax news agency quoted an unnamed source as saying the blast, which occurred when the train was between two stations, was caused by a bomb filled with shrapnel.

At least ten people were killed, another 50 injured. The blast blew a huge hole in the side of one subway car and some victims were lying bleeding on the platform.

READ MORE: Joe Jonas And Sophie Turner Buy Waterfront Miami Mansion For $11 Million

Officials in Russias second largest city evacuated and closed all subway stations as investigators searched the scene. Uber and other taxi services reportedly ran out of available cars in St. Petersburg Monday after the attack as people tried to make their way out of the city, according to CBS News.

A prosecutor’s office declared the incident a terrorist attack. Putin, who was in the city for a meeting with Belarus’s leader, said he was considering all possible causes for the blast, including terrorism. He was consulting with security services.

MORE NEWS: Space Florida Seeks Space Force Training Site

St. Petersburg emergency services at first said that there had been two explosions. But a source in the emergency services later said that there had been only one but that the explosion had occurred in a tunnel between stations.