The Hague, Netherlands ? Dutch police arrested 11 Greenpeace activists who boarded a cargo ship Saturday to stop it unloading newsprint paper they suspected was made from ancient trees felled in Canadian forests, the environmental group said.

The environmentalists delayed the ship Finwood from unloading its cargo at Terneuzen port, 130 miles south of Amsterdam, and hung a banner across its loading doors calling for newspapers not to use paper made from old established forests.

The group said activists climbed aboard the 560-foot ship and dangled from ropes in front of its unloading doors to prevent the paper being unloaded. Other protesters circled the ship in small boats.

Police ended the protest around midday by arresting 11 activists, and the ship was able to start unloading, said Greenpeace Netherlands campaign leader Hilde Stroot. It was not immediately clear if any of the activists were charged.

Stroot said companies in Canada every year cleared more than 1.7 million acres of forest that were home to threatened species such as lynx, wolf and caribou.

“Huge areas of forest are being destroyed for newspapers, books and toilet tissue,” Stroot said.

Greenpeace said the paper on board the ship was from Canadian forest products company Abitibi-Consolidated LLC and is used by all of the Netherlands’ major newspaper publishers.

Abitibi did not immediately return an after-hours call to its head office in Montreal.

The company’s Web site said its newsprint is made of up to 100 percent recycled paper, but Greenpeace claimed samples they have had tested contained up to 90 percent new wood fibers.