NATO Secretary General Jens Stoltenberg warned on Friday of the Russian military buildup in the Arctic and China's growing interest in this part of the world.

During a visit to northern Canada, Stoltenberg said the shortest route to North America for Russian missiles and bombers is over the Arctic.

He said Russia has established a new Arctic command and opened hundreds of new military sites dating back to the previous Soviet era in the Arctic, including airports and deep-water ports.

Stoltenberg said at a Canadian military base in Cold Lake, Alberta: "We see a significant Russian military buildup with new bases and new weapons systems, as well as using the Arctic as a testing ground for their most advanced weapons, including hypersonic missiles."

Stoltenberg also pointed out that China has declared itself a "near-Arctic state."

He said Beijing plans to build the world's largest icebreaker and is spending tens of billions of dollars on energy, infrastructure, and research projects in the north.

Stoltenberg added: "Beijing and Moscow have pledged to intensify practical cooperation in the Arctic. This is part of a deep strategic partnership that challenges our values and interests."

He also pointed out that climate change is making the Arctic region more accessible to militaries and welcomed Canada's recent announcement that it will boost its defense spending.

Canadian Prime Minister Justin Trudeau, who accompanied Stoltenberg, showcased some of the spending and activities Canada is undertaking in the north.