U.S. Secretary of State Mike Pompeo said on Monday that Russia is behaving aggressively in the Arctic and China's actions there had to be watched closely as well, amid growing divisions in the polar region over global warming and access to minerals.

Speaking as he arrived in northern Finland for a meeting of nations with territory in the Arctic, Pompeo said China appeared to have national security aims there, and Russia's activities, including plans for new shipping channels from Asia to northern Europe, deserved a closer look, as reported by Reuters.

"The United States and Arctic nations welcome transparent Chinese investment that reflect economic interests, not national security ambitions," Pompeo said in a speech.

Read alsoBritish forces to step up Arctic deployment to protect NATO's northern flank from Russia – media

Countries have been scrambling to claim territory or, like China, boost their presence in the region as thawing ice raises the possibility of exploiting much of the world's remaining undiscovered reserves of oil and gas, plus huge deposits of minerals such as zinc, iron and rare earth metals.

Pompeo said all were welcome to share in the Arctic's wealth, but raised doubts about the aims of Russia and China, both of which have been increasing their presence in the region.

"The Pentagon warned just last week that China could use its civilian research presence in the Arctic to strengthen its military presence, including by deploying submarines to the region as a deterrent against nuclear attacks," he told delegates at the conference in Rovaniemi, Finland.

"We need to examine these activities closely, and keep the experience of other nations in mind. China's pattern of aggressive behavior elsewhere will inform how it treats the Arctic."

Russia has also been boosting its presence, reopening military bases closed after the Cold War and modernizing its powerful Northern Fleet to safeguard its interests.

"In the Northern Sea Route, Moscow already illegally demands that other nations request permission to pass, requires Russian maritime pilots to be aboard foreign ships, and threatens to use military force to sink any that fail to comply," Pompeo said.

"These provocative actions are part of a pattern of aggressive Russian behavior in the Arctic."

The Arctic Council is made up of the United States, Canada, Russia, Finland, Norway, Denmark and Iceland. The region's indigenous populations are also represented.