Eight people were injured in a knife attack in the Siberian city of Surgut, Russian media agencies reported, citing the spokesman for the local office of the Russian law enforcement committee.

"A man was running along the main streets stabbing people", the TASS news agency reported.

The law enforcement committee said on its web site that "the attacker has been killed".

A committee member declined to comment on whether the incident was being investigated as a potential terrorist attack.

The state-owned RIA Novosti agency said two people were in critical condition in hospital.

It happened at about 11.20am local time, Russia Today reported.

Surgut, with a population of about 320,000, is an oil- and gas-producing centre 2,100km (1,300 miles) northeast of Moscow.