Russia declared a federal state of emergency in the Krasnoyarsk region as pollution from a diesel spill in the Arctic city of Norilsk drew comparisons with the Exxon Valdez accident off Alaska in 1989.

A fuel tank at a power station in the remote, industrial region lost pressure on May 29 and leaked 20,000 tonnes of fuel and lubricants, the Investigative Committee, a law enforcement agency, said. Much of it flowed into the river Ambarnaya.

Russian President Vladimir Putin approved the state of emergency in Norilsk on Wednesday. Putin said he supported the declaration as it would help in the clean-up.

At a televised government meeting to discuss the spill, Putin said he was shocked to find out local authorities had only learned of the incident from social media two days after it happened and scolded the region's governor Alexander Uss on air.

The state environment watchdog said 15,000 tonnes of oil products had seeped into the river system with another 6,000 into the subsoil. The state fisheries agency says the river will need decades to recover.

An expanse of crimson water could be seen stretching from shore to shore down a river and one of its offshoots in aerial footage published by the RIA news agency this week.

Norilsk, a remote city of 180,000 people, is situated 300 km (190 miles) inside the Arctic Circle. It is built around Norilsk Nickel, the world's leading nickel and palladium producer.

The company says it is doing all it can to clear up the spill and it has brought in specialists from Moscow, who have sectioned off the affected part of the river to stop the oil products spreading further.

(With input from Reuters)