The U.S. Minerals Management Service (MMS) said it will offer oil and gas exploration rights next month to 29.7 million acres in the remote Chukchi Sea off northwestern Alaska, the first in the Chukchi since 1991. It comes days before the U.S. Fish and Wildlife Service will decide whether to list the polar bear as threatened and has drawn fire from environmentalists seeking to limit oil development in the area.

In the past, companies seeking to drill Alaska's offshore regions have concentrated on areas as close to shore as possible, minimizing distances from infrastructure and potential costs. It is unclear whether companies will want to venture into such distant waters, said MMS spokeswoman Robin Cacy. Environmentalists say the Chukchi area, already hard-hit by rapid warming, should not be opened to more oil and gas development.

U.S. Senator John Kerry, a Massachusetts Democrat, criticized the lease sale plan and said the MMS should wait at least three years to investigate potential impacts to polar bears, being considered for Endangered Species Act protections because of habitat loss.