After a 40-year dispute, Russia and Norway signed an Arctic border treaty on Wednesday that will pave the way for offshore oil and gas exploration.
President Dmitry Medvedev and Norway's Prime Minister Jens Stoltenberg presided over the signing in Murmansk, a Barents Sea port city near the Norwegian border north of the Arctic Circle.
The disputed territory covered 175,000 square km (67,600 sq miles), an area about half the size of Germany, mainly in the Barents Sea between proven petroleum reserves on the Russian and Norwegian sides.
"The signing of the agreement, on which negotiations began back in 1970, marks a historic breakthrough in relations," the Kremlin said in a statement. Medvedev and Stoltenberg struck a preliminary deal in April.
"It is a practical example of the principle that all possible disputes in the Arctic should be solved by the Arctic states themselves though negotiations on the basis of existing international law."
Canada, Russia, Norway, the United States and Denmark, the only nations with Arctic coastlines, are racing to file territorial claims over oil, gas and precious metal reserves that could become more accessible as the Arctic ice cap shrinks.
International law states that the five have a 320 km economic zone north of their borders, but Russia is claiming a larger slice based on its contention that the seabed under the Arctic is a continuation of its continental shelf.