Russia and Norway say they have finally agreed to divide the Barents Sea.
The preliminary deal was struck during a two day visit by president Dmitry Medvedev to Oslo.
Norway’s Prime Minister Jens Stolenberg said both sides envisaged splitting the disputed area nearly in half. The agreement should pave the way for a final accord, ending a decades old energy row.
The border rift has meant Europe’s top two energy suppliers have not tapped into the Artic maritime zone, known to have vast gas and oil wealth.
The thawing in relations between Moscow and Oslo could also have wider global ramifications for how the rest of the Artic is divided.
Along with Russian and Norway, the US, Canada and Denmark all have territorial claims in a region that is becoming increasingly accessible because of climate change and new technology.