At least nine people were dead, including five children, after a gunman opened fire in a school in the central Russian city of Izhevsk, investigators said Monday.

"Nine people were killed because of this crime, including two security guards of the educational institution and two teachers, as well as five minors," Russia's Investigative Committee said in a statement on Telegram.

It added that the attacker "committed suicide".

According to investigators, "he was wearing a black top with Nazi symbols and a balaclava" and was not carrying any ID.

"His identity is currently being established," investigators said.

Russia's interior ministry also said there were about 20 people injured in the attack.

The region's governor Alexander Brechalov confirmed there were "casualties and wounded among children", speaking in a video statement outside school No88 in Izhevsk.

Rescue and medical workers could be seen working at the scene in the background, some running inside the school with stretchers.

A city of around 630,000 people, Izhevsk is the regional capital of Russia's Udmurt Republic, located around 1,000 kilometres (620 miles) east of Moscow.