The extremist group Islamic State (IS) has claimed responsibility for an attack on a supermarket in the Russian city of St. Petersburg that injured 10 people on December 27.
The claim was made by the IS's Amaq news agency on December 29.
It offered no evidence for its claim. The IS often claims responsibility for terrorist attacks worldwide that are carried out by people inspired by the extremist group but often with no formal ties to it.
Russian President Vladimir Putin said one day after the blast that the explosion was a terrorist act, and urged security forces to "take no prisoners" when dealing with imminent threats from terror-plot suspects.
Investigative Committee spokeswoman Svetlana Petrenko said on December 27 that the "homemade bomb" that ripped through a customer locker area at a Perekryostok supermarket exploded with the power equivalent to 200 grams of TNT.
But law enforcement authorities initially opened an investigation on suspicion of attempted murder, seeming to suggest that terrorist motives were not suspected.
Based on reporting by Reuters and dpa