The lawsuit filed in U.S. District Court in Anchorage claims that federal officials violated laws designed to protect the animals and their sensitive habitat in the Arctic waters of the Chukchi Sea.

"These regulations set the parameters for how oil exploration will be done in the next five years," said Brendan Cummings, oceans program director at the Center for Biological Diversity, which filed the suit along with Pacific Environment. "The Chukchi Sea is critical habitat for those animals. For them to survive in the face of global warming, we simply cannot allow oil development there."

Last month, the U.S. Fish and Wildlife Service decided to grant legal protection to seven oil companies in the Chukchi over the next five years should they accidentally harm "small numbers" of polar bears or Pacific walruses while drilling or during other exploratory activities. The agency is named as a defendant in the suit, along with Interior Secretary Dirk Kempthorne.