Groups of conservationists and Alaska Natives sued the federal government Thursday to stop a petroleum lease sale of a large area of the sea off Alaska.

The plaintiffs claim the environmental review by the Minerals Management Service did not fairly evaluate the potential effects if offshore petroleum fields were developed in the lease area, just smaller than Pennsylvania.

They also say the federal government has ignored changing conditions in the Arctic Ocean, including record low summer sea ice, that already are stressing polar bears, whales and other Arctic sea life.

"The Chukchi Sea is an ecologically rich frontier environment, and it is changing rapidly due to global warming," said Stan Senner, Audubon Alaska executive director. "We barely know this changing seascape, and this is not the time to move forward with a massive lease sale."

"We're in the process of reviewing it and will determine what we do after we've reviewed it," Minerals Management Service spokesman Gary Strasburg said of the lawsuit.

However, Alaska's lone U.S. representative, Don Young, condemned the lawsuit.

"These groups intend to use polar bears and the Endangered Species Act to shut down resource activities in Alaska the same way they used the spotted owl to shut down the timber industry in the Pacific Northwest," said Young, a Republican.

The groups want to stop domestic production of 15 billion barrels of oil and 77 trillion cubic feet of natural gas, he said.

The sale is scheduled for Wednesday in Anchorage. Earthjustice attorney Eric Jorgensen said the lawsuit does not seek an injunction to block the sale, but asks the court to declare leases invalid if they are sold improperly.

He said the groups hope federal authorities will cancel the sale based on the lawsuit and pending legislation. On Tuesday, U.S. Sen. John Kerry, D-Mass., introduced legislation to prohibit oil and gas exploration in the Beaufort and Chukchi seas until the full effect on polar bear populations was understood.

Jorgensen said the lawsuit seeks a more thorough environmental review. The groups claim the existing review lacked certain wildlife data and considered only one offshore field producing a billion barrels of oil, the minimum deemed economic to develop, even though more fields are likely to be developed.

Steve Oomittuk, mayor of Point Hope, an Inupiat Eskimo coast village of 737, said his community opposes any activity that endangers villagers' way of life.

"This is our garden, our identity, our livelihood," Oomittuk said. "Without it we would not be who we are today. Even at this present day and time, the animals from these waters shelter, clothe, and feed us."

Trish Rolfe, Alaska region representative of the Sierra Club, said it's irresponsible to move forward with a lease sale when no technology exists to clean up spills in broken ice.

"The biggest concern that we have is the risk of an oil spill in an Arctic environment and how that would impact not just wildlife and endangered species, but how it would affect Native villages that rely on the wildlife," Rolfe said.