Dec. 30 (UPI) -- Authorities arrested one person Saturday in the explosion at a shopping and entertainment center in St. Petersburg, Russia.
Russia's Federal Security Service said Saturday an unnamed person has been handed over to the Investigative Committee for interrogation and intended arrest in the explosion that injured 13 people Wednesday.
By Thursday morning, six of the injured were released from the hospital.
The agency said it "identified and detained the organizer and immediate perpetrator of the homemade explosive device blast in St. Petersburg 'Perekrestok' supermarket."
The Russian news agency Interfax reported the suspect is a resident of St. Petersburg with hardline nationalist views.
"Investigators have begun working with the suspected perpetrator of St. Petersburg explosion, he is being interrogated now. The investigation intends to request his arrest," Investigative Committee spokeswoman Svetlana Petrenko said in an RT report.
Russia's President Vladimir Putin earlier described the blast as a terrorist act.
Late Friday, the Islamic State claimed responsibility for the attack but it hasn't given any evidence supporting its claim.
In April, 14 people were killed when a suicide bomber detonated explosives in the city's metro system.
Earlier this month, the FSB detained Islamic State supporters who planned to also carry out explosions in the city.
The improvised explosive device had a power equivalent to 200 grams of TNT. It detonated inside a grocery store locker room where customers can leave their bags.
St. Petersburg Gov. Georgy Poltavchenko said that every victim of the incident will get $5,200 in compensation.