Russia (BBC), Jun. 4 – Russia's President Vladimir Putin has declared a state of emergency after 20,000 tonnes of oil leaked into a river within the Arctic Circle.

The spill happened when a fuel tank at a power plant near the Siberian city of Norilsk collapsed last Friday.

President Putin expressed anger after discovering officials only learnt about the incident two days later.

The plant is owned by a subsidiary of Norilsk Nickel, which is the world's leading nickel and palladium producer.

And in a televised video conference on Wednesday, Mr Putin lambasted the head of the company over the timeliness of its response.