Russian President Vladimir Putin has said that a blast that ripped through a supermarket in St Petersburg on Wednesday injuring 10 shoppers was an act of terrorism.
Nobody was killed in the explosion at a branch of Perekrestok in the north-western Kalininsky district of the city, and it was not immediately clear what the motive for the attack was.
Putin was speaking at an awards ceremony in the Kremlin for Russian military servicemen and women who served in Syria.
"You know that yesterday in St Petersburg a terrorist act was carried out," Putin told the audience.
"And that recently the Federal Security Service prevented another attempted terrorist act."
Putin said the security situation in Russia would be much worse however if thousands of Russian citizens who had fought with Islamic State in Syria had been allowed to return home.
Russia’s investigators say a device containing 200 grams of explosives had gone off at a storage area for customers’ bags.
It said the device had been rigged with shrapnel to cause more injuries.
“All possible versions of what has happened are being worked on,” said Alexander Klaus, the head of St Petersburg’s investigative committee.
“As of now, it has been established that 10 people were taken to the city’s hospitals with injuries. At the moment, the lives of those injured are not under threat.”
No one has claimed responsibility for the explosion in Russia’s second-largest city.
In April, an explosion on the St Petersburg metro system killed at least 13 people and injured more than 50 others.