JUNEAU, Alaska (AP) — The Biden administration said Friday it will restrict new oil and gas leasing on 13 million acres (5.3 million hectares) of a federal petroleum reserve in Alaska to help protect wildlife such as caribou and polar bears as the Arctic continues to warm.

The decision — part of a yearslong fight over whether and how to develop the vast oil resources in the state — finalizes protections first proposed last year as the Democratic administration prepared to approve the contentious Willow oil project.

The approval of Willow drew fury from environmentalists, who said the large oil project violated President Joe Biden’s pledge to combat climate change. Friday’s decision also completes an earlier plan that called for closing nearly half the reserve to oil and gas leasing.

A group of Republican lawmakers, led by Alaska U.S. Sen. Dan Sullivan, jumped out ahead of Friday’s announcement about drilling limitations in the National Petroleum-Reserve Alaska before it was publicly announced. Sullivan called it an “illegal” attack on the state’s economic lifeblood, and he predicted lawsuits.