Canadian actors Margot Kidder and Tantoo Cardinal have been arrested while protesting in Washington to stop construction of an oil pipeline from Alberta's oilsands to Texas.

Kidder, who played Lois Lane in the first four Superman movies, and her friend Cardinal, who starred in North of 60 and the film Dances with Wolves, were taken into custody near the White House.

They were among dozens arrested Tuesday morning on the fourth day of daily demonstrations against TransCanada Corp.'s Keystone XL pipeline project.

U.S. Park Police officers search women who were arrested with a group of about 40 demonstrators in front of the White House on Monday, the third day of protests against the Keystone XL pipeline. Chip Somodevilla/Getty

Kidder, born in Yellowknife and now living in Montana, was arrested first, according to photojournalist Shadia Wood, who witnessed the incident.

"We're the first state the pipeline goes through," the 62-year-old Kidder said before she was cuffed. "It's bound to leak, there's no way it's not going to.... They always assure us these things are safe, and they never are."

Moments later, U.S. Park Police took Cardinal into custody.

"They asked her to stand up and she did. And they placed her in handcuffs," Wood recounted. Cardinal was frisked and driven away, Wood said.

Expected to be released

Just as dozens of others since Saturday, Kidder and Cardinal were charged with failing to obey an order governing protests on the sidewalk, police said. Both were expected to be released later Tuesday.

Cardinal — who is from Fort McMurray, Alta., the heart of oilsands country — said she believes oilsands development is destroying the environment and making people sick.

"It's progressively broken my heart over time to see destruction that has gone on," she said. "Fort McMurray, the tarsands ... it's a place that we can see really how sick the Earth is and how sick we are as a people. I am here to be part of a voice to say, 'Wake up.'" The $7-billion Keystone XL pipeline has approval from Canada but needs a final nod from the United States before it can go ahead. It would nearly double the amount of crude the U.S. imports from Alberta's oilsands, and travel through environmentally sensitive areas of the American heartland to Gulf Coast refineries.

Opponents say Keystone is a disaster waiting to happen, pointing to a number of recent spills from pipelines. They also oppose Alberta's oilsands due to their high greenhouse gas emissions. Advocates say the pipeline will create thousands of American jobs amid a stubborn recession, and will also help end U.S. dependence on Middle Eastern oil.

With files from The Canadian Press