NATO Secretary General Jens Stoltenberg said on Thursday that cooperation between Russia and China in the Arctic poses a strategic challenge to the values ​and interests of the alliance.

"Russia has significantly increased its military activity in recent years, setting up a new Arctic Command, opening hundreds of new and former Soviet-era Arctic military sites, including airfields and deep-water ports, and using the region as test-bed for novel weapon system," Stoltenberg wrote in an article for Canadian newspaper The Globe and Mail. "Russia’s ability to disrupt Allied reinforcements across the North Atlantic is a strategic challenge to the Alliance."

China is also expanding its presence in the region, declaring itself a "near-Arctic state" and planning to create a "Polar Silk Road" connecting it with Europe through the Arctic, Stoltenberg wrote.

"Earlier this year, Beijing and Moscow pledged to intensify practical co-operation in the Arctic, as part of a deepening strategic partnership that challenges our values and interests," the NATO chief wrote.

Stoltenberg added that Finland's and Sweden's accession to NATO would significantly strengthen the alliance's position in the Far North.

Russian Defense Minister Sergei Shoigu previously said that the official participation of Helsinki and Stockholm in NATO strategic planning and the possible provision of the territory of these states for the deployment of strike weapons would change the security conditions in the Baltic region and the Arctic, and would require a revision of approaches to the defense of Russian territory.

Read more: Russia new doctrine calls US, NATO main threats to national security

On October 29, 2021, the US Navy announced that its Sixth Fleet and Naval Striking and Naval Support Forces Nato Staffs (STRIKFORNATO) have begun operations in the Mediterranean and Black seas.

According to the US Navy's statement, the Sixth Fleet Operations staff works together [with NATO partners] to ensure security and stability in the region, without offering any additional details.

Nikolay Korchunov, Russia's Ambassador-at-Large for Arctic Cooperation, said on May 22 that the Arctic area has become an "international theater of military operations" since Finland and Sweden filed for NATO membership.

"We are seeing an increase in international military activity in polar latitudes. There is the internationalization of military activities. The transformation of the Arctic region into an international theater of military operations is, of course, a very disturbing trend. We cannot but be concerned about this," - Nikolay Korchunov

On May 24, it was reported that the US plans to invest billions in Arctic defense, including modernizing its Thule Air Base in Greenland, citing an American military report. The report detailed that neither Denmark nor Greenland had been informed of the plans.

Washington has given the go-ahead for "significant investments" in its northernmost outpost, citing Russia's "increasingly aggressive" behavior, the report added.

In response to this, Russian President Vladimir Putin signed on July 31, the Russian Navy Day, a new 55-page Russian naval doctrine that revealed that the expansion of the NATO and the United States' quest to control the oceans are the biggest threats to Russia.

The document mentions that the "main challenges and threats" to national security and development were the US' "strategic objective to dominate the world's oceans" and NATO's military infrastructure moving closer to Russia's borders.  

Read more: Russia: NATO expansion poses risks, relation with alliance critical