Canada's prime minister is expected to assert his nation's claim to the fabled Northwest Passage through the resource-rich Arctic at talks with President Bush that start Monday.

Canada claimed the passage in 1973 but competition to control the Arctic has intensified with global warming. Shrinking polar ice has raised the possibility of new shipping lanes and development of what one U.S. study suggested could be as much as 25 percent of the world's undiscovered oil and gas.

Russia sent two small submarines to plant a tiny national flag under the North Pole this month. Canadian Prime Minister Stephen Harper went to the Arctic earlier this month and announced Canada will build a new army training center and a deep-water port in the Northwest passage.

The summit involving Bush, Harper and Mexican President Felipe Calderon is largely about expanding economic cooperation among the three nations, but Harper will assert Canada's claim during a private meeting with Bush, Canadian officials said at a press briefing on the summit.

The United States and Norway also have claims in the Arctic, and the U.S. says the passage isn't Canadian.

"It is a strait for international navigation," U.S. Ambassador David Wilkins said in an interview. "That's not a unique view of the United States. That is the view shared by a majority of the countries in the world."

Harper has said Canada's new military installations will help back up Canada's claim to the waters and natural resources of the Northwest Passage, which runs below the North Pole from the Atlantic to the Pacific through the Arctic archipelago.

Stephen Clarkson, a political scientist at the University of Toronto, said bringing up the Arctic is a way for Harper to show Canadians he's not too close to the unpopular president.

"It's a gratuitous way to create a little distance between himself and Bush," Clarkson said.

Bush will meet privately with Calderon at Fairmont Le Chateau Montebello, a small summer retreat on the banks of the Ottawa river.

The U.S. government is poised to offer a major aid plan to Mexico to fight drug trafficking and violence. Bush may announce part or all the proposal during the summit if the details are completed in time. The effort is expected to help pay for equipment and training.

Bush will arrive Monday afternoon in Ottawa before taking a helicopter to Montebello, which is between Ottawa and Montreal. Hundreds of police officers lined the roads and river leading to Montebello over the weekend.