If war breaks out on the Korean peninsula, Canada could become embroiled because of a half-century-old United Nations military alliance, federal documents reveal.

South Korean soldiers take part in an exercise to defend against a possible attack from North Korea about 100 km southeast of Seoul on Nov. 23. (Jo Yong-Hak/Reuters)

Canada's military obligations in the volatile region are outlined in a briefing note prepared for Defence Minister Peter MacKay shortly after North Korea detonated a nuclear device last year.

The note by the Defence Department's policy branch, which was obtained by The Canadian Press, says the UN alliance could be used to generate an international fighting force if war erupts.

North Korea ratcheted up its war rhetoric Friday after its deadly artillery barrage on a South Korean island Tuesday.

Because Canada was one of the combatants in the Korean War, it became part of an organization known as the United Nations Command — or UNC — following the 1953 armistice that ended three years of war between North and South Korea.

"Recent tensions have caused ADM (Pol) to review Canada's military obligations on the Korean peninsula if armed hostilities were to erupt," the memo reads. "The UNC structure would be used as a means of force-generating and receiving and tasking any contributions that UNC Sending States may choose to contribute in the event of a crisis."

Canada was one 16 countries that took part in fighting the Korean War and all signed the July 27, 1953, armistice that paused three years of hostilities. North and South Korea have remained technically at war since then, but the armistice has been supervised by a UN military commission along the 243-kilometre long demilitarized zone between the two countries.

As the briefing note outlines, the main "fighting formation" that would take the lead in any new conflict is the joint United States-South Korea Combined Forces Command. But that joint command "includes under its strategic organizational umbrella the legacy United Nations Command (UNC)."

Canada remains a member of the UNC because it was one of the 15 "Sending States" that supplied troops to the Korean conflict, the memo says.

UN role unlikely, academic says

Paul Evans, the director of the Institute of Asian Research at University of British Columbia, said he doesn't believe the current situation will become a full-blown military crisis. If it does, he said, "it would be difficult to use the UNC structure in the event of a conflict except as an initial advice."

That's because the UN's role would be minimized by fact that Russia and China wield vetoes as permanent members of the all-powerful Security Council, said Evans.

"I have a hunch that the UN role, whatever its formalities are now through the military commission and other things, are likely to be superseded almost immediately by a coalition of the willing that would be led by the United States and South Korea."

Federal officials say there have been no "asks" to Canada for military support in the region.

The American aircraft carrier George Washington and the South Korean navy are to conduct a joint training exercise on Sunday. North Korea said Friday the exercise was a provocation that could push the region to the "brink of war."

The aircraft carrier USS George Washington, shown in July, will take part in an exercise with South Korea starting Sunday. The exercise was planned before a North Korean attack killed four South Koreans on Tuesday. (Lee Jin-man/Associated Press)

Evans said it is not inconceivable that a Canadian navy warship could find itself operating in South Asian waters in the coming months, either as an add on to any continued U.S. navy presence or part of a stepped up international effort to interdict North Korean vessels.

Canada announced last month that it was adopting a "controlled engagement" policy, ending all official bilateral contacts between Ottawa and Kim Jong Il's regime in Pyongyang.

The government said the move was in retaliation for the fact a North Korean torpedo sank a South Korean warship this past March, killing 46 sailors.

Canada contributed three military experts to the international investigation that eventually pointed the finger at North Korea.

3 Canadian soldiers in S. Korea

The briefing note indicates Canada's military footprint in the Korean peninsula today is very light. Canada's defence attaché to Seoul, a colonel, and his assistant, a sergeant, represent the country on the UNC.

Canada's defence attaché in Tokyo represents Canada at the UNC's "rear" headquarters in Japan. And Canada also contributes a major to the Korean Army Staff College.

The censored briefing note does not elaborate on what would follow if a "crisis" erupted and an international military coalition had to be created.

Mark Sedra, the head of the global and human security program at the Centre for International Governance Innovation in Waterloo, Ont., said Canada has offered political support to South Korea, but he doesn't see a military role.

"That would require a big escalation of the situation if you were to see a multinational force commitment. If we see that happening, we've really seen a deterioration of the situation."

Prime Minister Stephen Harper "strongly condemned" North Korea's artillery attack Tuesday, calling it "the latest in a series of aggressive and provocative actions" by the dictatorship.