Advanced Conservation Strategies, in a report commissioned by Chile and Argentina, says hunters are needed to kill thousands of beavers, The Observer reported Sunday.

If adopted, the plan calls for the largest eradication project attempted by conservationists, the British newspaper said.

"I have seen the impact of all sorts of animals introduced to new habitats, but I have never seen anything like the damage inflicted by these beavers," said Josh Donlan of Advanced Conservation Strategies. "They move along rivers and lay waste to their banks. It looks as if bulldozers have been let loose. Millions of acres have been wrecked."

The newspaper reported that 50 North American beavers were introduced to Tierra del Fuego in southern South America in the 1940s in order to establish a fur trade. Since then, their numbers have multiplied dramatically.

What has happened in South America is seen as a warning by opponents of Britain's beaver reintroduction project.

Several sites in Scotland and England have already been earmarked to reintroduce the European beaver, a close cousin of the American beaver, back to Britain after the animal was hunted to extinction in the 16th century.