MOSCOW (AP) — Russian President Vladimir Putin says Wednesday's explosion at a supermarket in the country's second-largest city was a terrorist attack.

At least 13 people were injured Wednesday evening after an improvised explosive device went off at a storage area for customers' bags at the supermarket in St. Petersburg. Investigators say it was rigged with shrapnel to cause more damage.

No one has claimed responsibility for the attack.

Putin spoke Thursday at a military awards ceremony at the Kremlin but did not offer any details.

The president previously has spoken about Russia's operation in Syria as a pre-emptive strike against terrorism at home.