Arctic oil reserves (in billions of barrels above) are largely under the ocean

An estimated 30% of the world's undiscovered gas and 13% of its undiscovered oil may be in the Arctic, according to a map published on Friday.

The map is the culmination of an assessment carried out by the US Geological Survey (USGS).

Writing in the journal Science, its authors say the findings are "important to the interests of Arctic countries".

But, they add, they are unlikely to substantially shift the geographic pattern of world oil production.

According to the new map, the majority of oil is likely to be found underwater, on continental shelves.

Russia has sought to claim its rights to the Arctic

Surrounding nations, including Russia, United States, Canada, Denmark and Norway, have all already sought to assert their jurisdiction over parts of the Arctic.

In 2007, two Russian civilian mini-submarines descended to the seabed to collect geological and water samples and to drop a titanium canister containing the Russian flag.