People gather outside a supermarket after an explosion in St Petersburg, Russia December 27, 2017. (REUTERS PHOTO)

MOSCOW, Dec. 30 (Xinhua) -- The suspect of an explosion in a St. Petersburg supermarket that took place on Wednesday was detained and being interrogated, Russian authorities said Saturday.

An explosive device placed in a locker went off at a supermarket in a shopping center in St. Petersburg on Wednesday, injuring at least 13 people.

The Russian Federal Security Service (FSB) said in a statement that it had identified and detained the organizer and direct executor of the bombing and handed over the suspect to the Russian Investigative Committee for further investigation.

Russian investigators immediately began to work with the suspect, who is currently being interrogated, according to a separate statement by the Investigative Committee.

The investigation team intends to request the court to arrest the suspect, it added.

On Thursday, Russian President Vladimir Putin said that the latest bombing in St. Petersburg was an act of terrorism.