Bomb rips through St Petersburg supermarket with shrapnel injuring 10 Christmas shoppers

The incident comes several months after Russia's second city was rocked with a metro bombing in April which killed 16 people

The device, containing 200 grams of explosives went off at a storage area for customers' bags, Russia's Investigative Committee said.

Earlier this month, Putin called U.S. President Donald Trump to thank him for Central Intelligence Agency information that helped prevent a terrorist attack in St. Petersburg.

The motive for the attack was not immediately known. According to a spokesman for the governor of St. Petersburg, one person was in serious condition.

Russian authorities characterized the bomb as a "homemade explosive device" stuffed with "killing agents", apparently a reference to ball bearings used as shrapnel in the device. Eight of the injured remained hospitalized. Putin told Trump the information helped lead to the arrest of terrorists that had planned the attack.

Map of Russia locating Saint Petersburg where an explosion in a supermarket has injured at least four people

An investigator works inside the supermarket after an explosion, in St. Petersburg, Russia, Thursday, Dec. 28, 2017.

Putin made the statement during a military decoration ceremony Thursday, mentioning another recent attempt that was prevented by the the Federal Security Bureau. Over 50 people have been evacuated from the building.

During his remarks at the Kremlin awards ceremony, Putin said Russia's 2-year military campaign in Syria helped eliminate militants who threatened Russian Federation.

"What would have happened if those hundreds, thousands. had come back to us, trained, armed and well-prepared?"