One of the most powerful politicians in the U.S. said that while Washington wants to wean itself off foreign oil, Canada is the exception because it isn't "foreign," according to Alberta Premier Ed Stelmach.

The comments came as U.S Speaker of the House of Representatives Nancy Pelosi met with politicians, environmentalists and First Nations leaders in Calgary.

"She didn't consider Canada to be foreign oil," Stelmach said Thursday, noting that the politicians also spoke about his province's efforts in renewable energy during their dinner meeting on Wednesday.

Stelmach, Saskatchewan Premier Brad Wall and Quebec Premier Jean Charest were in on the Wednesday night meeting, along with federal Environment Minister Jim Prentice.

While Canada is a large supplier of energy to the U.S., a growing backlash against the oilsands has raised questions about its sustainability and environmental impact.

"Let's not be naive," Stelmach told reporters in Calgary. "One dinner may not alter or change a lot of positions or opinions by either the environmental groups or some of the elected officials, but we did have significant agreement in a number of areas."

Pelosi also met with First Nations groups and environmental agencies on Thursday to hear the other side of the argument.

One of those groups is Environmental Defence, whose executive director Rick Smith took issue with Stelmach's characterization of the oilsands.

Smith said the U.S. has never threatened to cut off Canadian oil imports, and he said that Stelmach was creating a "straw man" to distract from the real issues of pollution and climate change.

He noted that Pelosi was "in listening mode" during their consultations, and he added that she especially thanked First Nations leaders who spoke Thursday, as they "put a face" on the oilsands' environmental impact.

Smith, speaking with CTV News Channel, said Alberta wants to drastically increase oil production without "coming up with a game plan" to deal with the fallout on the region's ecosystem.

Smith also alluded to the latest in a line of reports that suggest the environmental impact of the oilsands may be much more severe than government or industry estimates indicate.

Marlo Raynolds, a climate change consultant with the Pembina Institute think-tank, said that Canadian politicians need to show more leadership in capping growth of the oilsands.

During a meeting Thursday, Raynolds said Pelosi expressed plans to legislate the U.S. away from oil and other fossil fuels.

"It's the type of leadership that we really need to see in Canada," Raynolds told News Channel from Ottawa.

While Raynolds stopped short of calling for the closure of the oilsands, he said that some serious caps need to be put on its expansion.

"We have to put into question further expansion of the oil sands resource," he said.

"We have to set absolute limits on environmental impacts, or else we cannot do this responsibly."

Meanwhile, Saskatchewan's premier said he made the point that Canada's oilsands industry is constantly striving to improve its green business practices.

He said Pelosi was in Canada to listen and learn about our oil industry, and was a knowledgeable and engaged participant in the discussion.

Wall said he and Stelmach espoused initiatives that are underway to reduce the carbon footprint in the oilsands. The goal was to convince Pelosi that Canada's oil is a sustainable investment for the U.S., which is the largest purchaser of the product.

Prime Minister Stephen Harper spoke to Pelosi on Thursday about her oilsands meetings and about a number of other issues, according to a statement from his office.

Liberal foreign affairs critic Bob Rae spoke with the veteran American legislator at a breakfast meeting on Thursday, noting that her powers as speaker of the House of Representatives "are significant."

"It should not be unusual for us to be meeting with our colleagues from the United States," Rae added. "We obviously share a great deal in North America. Our economic ties are intensely close."