Ten people were injured and sent to hospitals when a homemade bomb detonated in a supermarket in St. Petersburg, Russia, officials said Wednesday.
"According to preliminary information, an explosion of an unidentified object occurred in a store," Investigative Committee spokeswoman Svetlana Petrenko said in a statement.
The blast was caused by a "homemade explosive device with the power equivalent to 200 grams of TNT filled with lethal fragments," she said.
Investigators said they have opened a criminal case on the grounds of attempted murder.
Health officials said none of the 10 victims suffered life-threatening injuries.
The motive for the attack was not immediately known.
