Russia, already the owner of the world's longest Arctic coastline, has spent the past few years bolstering its presence there.
Now changes wrought by climate change are giving Moscow more territory to work with in the Arctic as the US is still looking for ways to get into the high north.
Russian sailors and researchers explored five new islands around the Novaya Zemlya archipelago in the Arctic Ocean off Russia's northern coast during an expedition in August and September.
The islands, ranging in size from about 1,000 square yards to 65,000 square yards, were first spotted in 2016 but not confirmed until the expedition by Russia's Northern Fleet and the Russian Geographical Society.
The new islands are "associated with the melting of ice," expedition leader Vice Adm. Aleksandr Moiseyev said on October 22, according to state news agency Tass. "Previously these were glaciers, but the melting of ice led to the islands emerging."
The discoveries come as Moscow has boosted its military presence in the region, refurbishing Cold War-era bases, setting up new units, opening ports and runways, and deploying radar and air-defense systems.
In all, Russia has built 475 military facilities in the Arctic over the past six years and deployed personnel, special weapons, and equipment to them, Defense Minister Sergei Shoigu said in March.
US officials regard Russian activity in the Arctic as "aggressive" and have questioned their Russian counterparts on it.
"When I was as at the [Arctic Conference in 2017] and [with] the Russian ambassador ... I asked him, 'Why are you repaving five Cold War airstrips, and why are there reportedly 10,000 Spetsnaz troops up there?'" Navy Secretary Richard Spencer said at a Brookings Institution event on October 23, referring to Russian special operation forces.
"He said, 'search and rescue, Mr. Secretary,'" Spencer added.
Asked whether Russia was a competitor or partner or both in the Arctic, Spencer said he "would love to say both" but expressed concern.
"I worry about their position there," he said, pointing to the Northern Sea Route, which cuts shipping time between Europe and Asia by 40% compared to the Suez Canal route but runs through Russia's Exclusive Economic Zone. In April, Moscow said foreign ships using that route would have to give notice and pay higher transit fees.
"That said, dialogue must remain open. We have to keep those avenues of communication," Spencer added. "You've seen the arguments compared to the Suez Canal, the time and dollar savings by going over north, that's happened. It's going to continue to happen. We have to be present."