13 people injured in St Petersburg blast

According to the latest information, eight of the injured remain in hospitals. Earlier reports said the blast had left ten people injured.

"As of 08:00 (on December 28), the total number of people injured in the blast in a supermarket in Kondratyevsky Avenue is 13. Of these, five refused to be taken to hospital. Five of those remaining in hospitals are in a moderately grave condition, while three are in a satisfactory condition," Mityanina said.

There are no children among those injured, the press service of the city's healthcare committee said.

An explosion at a supermarket in St Petersburg's Kondratyevsky Avenue was reported Wednesday  night. According to preliminary reports, an unidentified explosive device was detonated in the Gigant-Hall entertainment center on the first floor near self-storage lockers of the Perekrestok supermarket.

Chairman of the Russian Investigative Committee Alexander Bastrykin has dispatched experienced investigators and experts from Moscow to look into circumstances.

The Investigative Committee defined the explosion as an attempted murder against two and more persons. The investigators say that an improvised nail bomb with a power equivalent to 200 grams of TNT was detonated in the supermarket.