Thousands of minks escaped from a fur farm in western Denmark — possibly set free by animal rights activists, police said Monday.

Authorities and residents were chasing down about 5,000 minks from the farm near Asp, 200 miles northwest of Copenhagen, police said.

Investigators believe animal rights activists raided the farm overnight to set them free but no suspects have been identified, police spokesman Knud Lauridsen said.

Animal rights activists also are suspected of setting some 2,500 minks free from a farm in Finland in August.

Denmark is one of the world's largest producers of mink fur, with Danish fur farmers raising more than 12 million minks every year.