A Canadian military surveillance aircraft monitoring United Nations sanctions was harassed in international airspace off North Korea by the Chinese military — part of "a pattern of behaviour that's inappropriate," Canada's top military commander said Wednesday.

The incident involving a CP-140 Aurora, which has since returned home, took place in October as allied nations monitored the sea lanes for cargo ships and tankers intent on violating embargoes imposed on North Korea by the UN Security Council.

"We have been interfered with on our flights in the area and been challenged inappropriately in international airspace," Chief of the Defence Staff Gen. Jonathan Vance said in a year-end interview with CBC News.

The Chinese, he said, flew too close to the sophisticated maritime patrol planes, used improper radio procedure and "inappropriate language."

Vance referred questions about the specifics to National Defence officials, who were less than forthcoming.

They conceded having "contact with the Chinese Air Force operating" near North Korea and insisted that "at no time were our crews or aircraft put at risk."

Tensions with China spiking

Japan, Australia and New Zealand also have conducted enforcement flights and Vance said their aircrews have experienced similar harassment.

The Canadian patrol planes conducted 12 missions off North Korea in October and ran across the Chinese air force on 18 occasions. Of those 12 missions, four had no interactions with Chinese military aircraft, one had a single interaction and seven had "multiple interactions," says a statement from National Defence.

Some in the diplomatic community, speaking on background Wednesday, said they see the incidents as China attempting to remind the West that they're in a region that is very sensitive to them — one where they are the predominant power.

The badgering involving the Canadian patrol aircraft happened before the recent spike in tension over Chinese telecommunications giant Huawei — including the arrest in Vancouver of a top company executive, Meng Wanzhou, 46, and the detention of three Canadian citizens in China.

Canadian warship HMCS Calgary and the supply ship MV Asterix recently returned to Esquimalt, B.C. from sanction enforcement patrols in the North Korea region.

Vance said their experience was different and they "did not face overt interference, but it's made very clear to anybody that's in that region that you're in China."

The Canadian military has, along with its allies, also faced "a persistent cyber threat that we are relatively well-poised to counter," said Vance.

But the recent sanctions-related provocation represents a troubling "pattern of behaviour" that undermines freedom of navigation, both on the sea and in the air, he said.

Vance said it also has important implications for Canada — especially when it comes to Beijing's increasing interest in the Arctic.

In a major policy statement earlier this year, China declared itself a "near-Arctic state" and promised to build a "Polar Silk Road" along Canada's northern border.

"China attaches great importance to navigation security in the Arctic shipping routes," says the country's Arctic Strategy, which was published by Chinese state media in January.

Beijing's overall policy, officially known as the 'Belt and Road Initiative', involves plans to open up new trade corridors through the construction of new ports, roads, rail links and trade agreements around the globe.

China has spent tens of billions of dollars on oil and gas projects in Siberia and in waters off Russia. State-owned mining companies have also bought into rich mineral deposits in Greenland.

War in the Arctic still unlikely: Vance

Adam Lajeunesse, a fellow at the Canadian Institute for Global Affairs, argued in a new policy paper that all of the activity and posturing by China "is not a direct threat to Arctic-state interests and that mutually productive activity is possible."

He said the threat is being overblown and "the values espoused in the Chinese document — environmental preservation, co-operation, consultation, support for Indigenous communities and science-based policy-making — strike many of the same chords as Canadian policy under the Liberal Party."

Vance said he does not believe there is a threat of military confrontation in the Arctic, but he worries about China's tactics of intimidation and its willingness to ignore international rules — which Beijing has demonstrated with its construction of artificial islands in disputed areas of the South China Sea.

"China is a valued trading partner. China is a valued member of the international community," he said. "China has enormous influence and stakeholdership in that part of the world.

"We respect that. We all do, but there is another side of the coin. At the same time, we face challenges."

The threats are not "insurmountable" and can be handled through diplomacy and dialogue, Vance said.

China does not pose the same type of challenge as Russia, which has demonstrated its own willingness to ignore international rules.

The lessons, Vance said, should not be lost on leaders and policymakers. "For countries like Canada, any disturbance or the failure to abide by [international] norms can indicate problems.

"Ask Ukraine. Ask any nation that has had a belt and road initiative forced upon it."