Russian knife rampage leaves 'at least six injured, one critical' in St Petersburg

At least six people have been injured in a knife attack in St Petersburg, Russia, according to local media.

The incident reportedly happened at the O'KEY supermarket on Kosmanotov Street, causing panic and mayhem among shoppers.

A security guard and a woman are reported to have been seriously injuries and have been rushed to hospital. The security guard was stabbed twice by the knifeman.

The other four victims refused to be taken to hospital, according to local media.

A 44-year-old man has been detained by police in relation to the attack and has been taken away for questioning. He was overpowered by the supermarket's security guards before the police arrived, it is reported.

Video images released to social media channels show the aftermath of the horrific attack. Trails of blood can be seen on the supermarket floor and a woman is filmed lying on her back and holding her throat with her hands.

Someone can be heard asking if there is a doctor in the store, before telling a person to run to a nearby pharmacy to see if there were any medics there.

An eyewitness recounted the terrifying moment a man started to attack people in the supermarket.

A woman claimed to : "The idiot began throwing bottles of champagne and grabbed a knife.

"He started running around the store. Naturally, we all ran away from him, quickly abandoning everything.

"Well, as a matter of fact, in the middle of the hall he caught up with some woman and stabbed her in the chest with a knife, from above.

"And there he either cut himself somehow, fell over, [or he] was already dumped there. Now the ambulance has arrived, the woman is lying and he is already surrounded by police officers."

's Investigative Committee has launched a criminal investigation into the incident. Detectives are combing through the supermarket, collecting evidence.

A policeman who arrived at the scene of the attack told reporters: "Upon arrival at the supermarket, we saw a security guard injured on the street, bleeding.

"We approached him directly, provided first aid, and applied a tourniquet. We then proceeded directly to the store itself, where there were still victims."