MOSCOW: A man armed with a knife launched an attack in a hypermarket in Russia’s northwestern city of Saint Petersburg on Friday, injuring four people, investigators said.

While knife crime is common in Russia, such public attacks are rare.

The motive for the crime was unclear.

The Investigative Committee for Saint Petersburg said the unnamed man “attacked shoppers and stabbed them with a knife” in a branch of Okei hypermarket.

“Four victims with wounds of varying severity were hospitalised” and the “suspect was detained at the scene of the crime”“ investigators said.

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They have launched a probe into attempted murder.

Police spokeswoman Irina Volk said officers had disarmed the “aggressive” man.

A video released by police showed a man in a black jacket, presumed to be the suspect, lying on the floor with his head bandaged and a knife with drops of blood around it.

The Fontanka local news website reported a 44-year-old man had been arrested, saying police had described him as a “lowlife type”.

It posted security camera footage of a man running through aisles with a knife and a bottle and attacking a woman, as well as a video of a customer lying on the floor in the meat aisle.

A woman who said she witnessed the attack told the website “a weirdo… started throwing bottles of champagne and pulled a knife”, prompting customers to flee.

“He ran up to some woman in the middle of the store and stabbed her in the chest,” she said.