Russia has staked out a further vast chunk of the Arctic.
The country’s foreign ministry says it has submitted a claim to the UN for 1.2 million sq km of sea shelf.
The move comes as competition escalates for oil and gas. The Arctic is believed to be rich in both.
An earlier claim, made in 2002, was returned to Russia by the UN for lack of evidence. Russian authorities say the resubmission is backed by new arguments.
But the country had already made a symbolic claim to the seabed when in 2007 it used a submarine to drop a canister holding the Russian flag onto the ocean floor.
Russia is not alone in trying to stake territory. The US, Canada, Denmark and Norway have all been trying to gain jurisdiction over parts of the Arctic. Shrinking polar ice is giving new exploration opportunities.
Russia is increasingly active in the Arctic. It has reopened a military base created by the Soviets on the New Siberian Islands and created several other military outposts. It claims these are to protect shipping routes across the Arctic Ocean to the Pacific.