The Siberian Shelf in the Arctic Ocean is the largest (and least explored) of the Russian shelves, a region of strategic importance because of its oil and natural gas reserves. Other parts of the Russian shelf are typically named after the corresponding seas: Barents Shelf (Barents Sea Shelf), Chukchi Shelf (Chukchi Sea Shelf), etc. With the exception of internal Russian seas, these geological shelves are shared with other countries which share the corresponding seas. For example, the Chukchi Shelf is shared between Russia and the United States according to the 1990 USA-USSR maritime boundary.