Russian oil company Rosneft said Monday it started an exploration program in the Barents Sea with Norwegian energy company Statoil.

"The start of this exploration operation marks an important milestone in developing the cooperation between Rosneft and Statoil," the Russian company said in a statement. "The companies plan to implement their experience of exploration and development of hydrocarbon fields in regions with harsh climate."

Rosneft said its subsidiary RN Nordic Oil is working alongside Statoil at the Pingvin license area of the Barents Sea.

Statoil last week received approval from the government to move the Transocean rig, Spitsbergen, to the area. Rosneft said both sides would review the drilling results from the region through the end of the year.

Statoil was the target of a campaign from Greenpeace, which said exploration in the arctic waters of the Barents Sea puts the region's ecology at risk.

The Norwegian government said explorers would have to wait out a comment period before drilling into any oil-bearing layers of the Pingvin license.

Rosneft is the target of Western economic sanctions imposed in response to Russia's stance on crises in Ukraine.

There was no corresponding statement on the work with Rosneft from Statoil.