Environmental groups filed a lawsuit against energy-rich Norway on Tuesday to stop oil drilling in the Barents Sea.

Greenpeace Nordic and Norwegian group Natur og Ungdom (Nature and Youth) accused the government of violating the Paris agreement on climate change and Norway's constitution by allowing companies to drill for gas and oil in the Arctic waters.

"The constitution obliges the state to guarantee a healthy environment, and definition of a healthy environment is linked to the commitments of the Paris agreement," Greenpeace Norway head Truls Gulowsen told AFP.

"We will argue in court that the Norwegian government has an obligation to keep its climate promises and will invoke the people's right to a healthy environment for ours and future generations," Nature and Youth head Ingrid Skjoldvaer said in a joint statement with Greenpeace.

"It will be against the people of the Arctic," she said.

- 'Act of hypocrisy' -

Norway, whose oil revenue is declining, in May provided 10 production licences covering a total of 40 blocks to 13 companies, including national oil major Statoil, Chevron and ConocoPhillips of the US, Germany's DEA, Japan's Idemitsu, Swedish Lundin, Austria's OMV and Lukoil of Russia.

The government believes it is abiding by the constitution and that the "validity of the licences cannot therefore be attacked on this basis," energy ministry spokesman Ole Berthelsen told AFP.

The three most disputed licences are located in a currently unexplored maritime border area, over which non-OPEC states Norway and Russia were bitterly at odds before reaching an agreement in 2010.

One of these areas is the northernmost ever open for exploitation, and environmental groups are concerned about its proximity to the disputed limits of sea ice.

Norway was one of the first countries to ratify the December Paris agreement, which aims to limit global warming to below two degrees Celsius above pre-industrial levels.

"Signing an international climate agreement while throwing open the door to Arctic oil drilling is a dangerous act of hypocrisy," Gulowsen said in a statement.

"By allowing oil companies to drill in the Arctic, Norway risks undermining global efforts to address climate change," he said.

Largely ice free due to the Gulf Stream, the waters now open for exploration are considered promising by the oil industry as Norway's crude production continues to decline since it reached a peak in 2000.

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