At least 10 people were injured in an alleged improvised explosive device (IED) explosion at a supermarket in St. Petersburg, Russia.
The city's governor's office said the IED detonation has left one victim in a serious condition.
Officials are investigating the explosion, which targeted the supermarket chain Perekrestok, as attempted murder.
However, they haven't ruled out any other motive, including the possibility of terrorism.
IED explosion at St Petersburg supermarket
Blast equivalent to 200g of TNT explosion took place
A device containing "striking" elements with a force equivalent to the detonation of around 200g of TNT explosive caused the blast, according to Russia's investigative committee.
The explosion occurred in the section of the supermarket that held lockers for storing bags.
The supermarket was immediately evacuated. No fire was reportedly caused but photos on social media reveal extensive damage to the store.
Major attack on St Petersburg planned by ISIS recently foiled
The explosion comes days after Russian President Vladimir Putin thanked his American counterpart, Donald Trump, after the CIA provided crucial information to Russian security agencies to foil a major ISIS attack on the Kazan cathedral in St. Petersburg.
In April, at least 13 people were killed and 50 injured in a bomb explosion on the St Petersburg metro system.