June 4 (UPI) -- Russian President Vladimir Putin declared a state of emergency for a region in northern Siberia after oil spilled from a power plant into a river.
A fuel tank at the plant in Norilsk ruptured on Friday, leaking 20,000 tons of diesel fuel into the nearby Ambarnaya River, contaminating portions of the waterway as far as 7 miles away from the site.
The plant's parent company, Norilsk Nickel, said it believes thawing permafrost caused one of the tank's pillars to collapse.
Permafrost thawing is linked to climate change and has caused issues including damage to roads and homes as well as disruptions to herding and agriculture throughout Siberia.
Greenpeace Russia issued a statement describing the incident as the largest oil spill in the history of the Russian Arctic, comparing it to the Exxon Valdez oil spill in 1989.
The Russian Investigative Committee opened a criminal inquiry into the spill and detained the plant's manager, Vyacheslav Starostin.
Putin said he would ask investigators to look into the spill and assess how officials responded.
He also criticized the company in a videoconference, questioning why he only learned of the spill Sunday.
"Why did the government agencies only find out about this two days after the fact?" Putin said. "Are we going to learn about emergency situations from social media?"
Norilsk Nickel, the world's leading producer of nickel and palladium, was responsible for another oil spill in 2016.
The company has dispatched hundreds of personnel to clean up the most recent spill, gathering 340 tons of oil.