Greenpeace advocates said they uncovered evidence of oil spills at the Mamontovskoe oil field in Siberia. It said oil spills have formed a "black lake" in the region that's been expanding "for several years."
Greenpeace said in a statement the Russian oil industry is among the worst polluters in the world. Russian oil company Rosneft was blamed for most of the spills.
"This environmental disaster is simply the daily routine of this oil giant that is now rushing to exploit the arctic," it said in a statement Monday. "Instead of replacing its leaky, rusty pipes in Siberia, it plans to invest billions of dollars into arctic shelf exploration."
Representatives from countries with territorial borders in the Arctic Circle, as well as Finland, Iceland and Sweden, agreed in May to improve ways in which oil spills in the region are addressed.
More than 10 percent of the undiscovered oil reserves and 30 percent of the undiscovered natural gas are believed to be in arctic waters. Changing weather patterns are leaving areas ice-free for longer periods, giving energy explorers access to new reserves.