MOSCOW, April 3 (RAPSI, Diana Gutsul) – Investigators have opened a criminal case over explosion in St. Petersburg metro, RAPSI learnt in Russia’s Investigative Committee on Monday.

According to preliminary data, on Monday, at around 2:40 PM Moscow time, an unknown device exploded in a train between St. Petersburg metro stations “Technological Institute” and “Sennaya Ploshchad” leaving several people dead and wounded.

Reportedly, at least 10 people died in the blast. The St. Petersburg Health Care Committee reported that twenty two people were wounded, including one child.

Russian President Vladimir Putin said that "causes for explosion have not been identified yet," as quoted by the Presidential press-service.