Russia filed a submission to the United Nations Tuesday for an additional 1.2 million square kilometres (463,000 square miles) of Arctic shelf.

In the submission to back a 2001 claim at the UN Commission on the Limits of the Continental Shelf, Russia said research showed it had rights over the swathe. The Arctic has become a theatre of international tension, with rival claims over a sea floor believed to be rich in minerals and hydrocarbons.