The former U.S. ambassador to Canada says that before leaving his position in 2005, he told his officials in the State Department that Washington should re-examine its territorial claims to the main Arctic waterway.

Canada claims the Northwest Passage, but the United States says the waters are international.

Paul Cellucci, in an interview with CTV's Question Period, said he raised the issue with the State Department and mentioned it to his successor in Ottawa, current ambassador David Wilkins.

"I think in the age of terror, it's in our security interest for the Northwest Passage to be part of Canada," Cellucci told co-host Jane Taber.

"That would enable the Canadian Navy to intercept vessels in the Northwest Passage, and make sure they're not trying to bring weapons of mass destruction into North America."

Cellucci's comments come after Prime Minister Stephen Harper's recent trip to the North, where he made a number of announcements aimed at strengthening Canada's territorial claims in the Arctic.

And it also comes a day before Harper and U.S. President George W. Bush are due to meet in Montebello, Que., for a security-related summit.

"It's in our interest to work together on security," Cellucci said. "My hope is that the United States will take a second look at our longstanding position, because I think it's in our security interests that this be considered a part of Canada."

"If the global warming continues, this will get a lot more attention," he added.

Last week in Resolute, Harper announced the 4,100-strong Canadian Rangers force will get a boost of 900 more members, and a deep-water military port will be constructed in Nanisivik.

Harper's trip came after a recent Russian submarine expedition that planted a Russian flag on the seabed at the North Pole.

Denmark is also mapping the Arctic ridge as the polar race heats up, trying to prove the 2,000-kilometre underwater mountain range is attached to the Danish territory of Greenland.

Canada, the United States, Russia and Norway have competing claims in the Arctic region, where a recent U.S. study suggests as much 25 per cent of the world's undiscovered oil and gas could be hidden.

The race for sovereignty has heated up partly because global warming is shrinking the polar ice, which could someday open up resource development and new shipping lanes.