By Lee Carter
BBC News, Toronto
A number of countries have made competing claims for the Arctic
Canadian Prime Minister Stephen Harper is on a five-day visit to the northern Arctic region of his country.
Mr Harper said it was all part of an initiative to promote Canada's sovereignty in the far north.
The prime minister observed a day of military exercises in Canada's eastern Arctic, home mainly to the indigenous Inuit people.
Canada's government is making the long-neglected north a priority, as other countries eye the region's resources.
About 700 Canadian military personnel are involved in Operation Nanook, three weeks of military exercises in the Canadian Arctic.
Mr Harper has now managed to see the operation up close for himself, first travelling by helicopter to a navy frigate and then by dinghy to a submarine which dove underwater for an hour-long warfare exercise.
Up until a few years ago, Canada took the vast, inhospitable northern reaches of its country for granted.
Mr Harper said Canada wanted the Arctic to reach its economic potential
Now, however, a number of other countries are citing interest in laying territorial claims to the region, including Russia, Denmark and the United States.
The people who live in the Canadian north, mainly the indigenous Inuit, say their needs have been largely ignored too.
Mr Harper said the two issues were inextricably linked.
"We know the gaze of other nations is increasingly focused here in our Arctic," he said.
"By working to reach this region's full economic potential, we are strengthening its people and we are strengthening the sovereignty of our country."
The Arctic nations are all in a race to put forward territorial claims before a United Nations commission.
The main focus is on the area immediately around the North Pole, where Russian, Canadian and Danish scientists have been mapping their continental shelves.