JUNEAU, Alaska — Conservation groups and an Iñupiat-aligned group sued Thursday to overturn the recent approval of an exploratory drilling program in the National Petroleum Reserve-Alaska, saying it was improperly analyzed by the federal government and could harm caribou and important habitat areas.

The U.S. Bureau of Land Management approved a one-year program proposed by ConocoPhillips Alaska last month that included seismic surveys aimed at helping identify oil and gas reserves and plans to drill four exploration wells. Activities would occur near existing ConocoPhillips Alaska developments, including the large Willow oil project, the lawsuit states.

The complaint, filed by Earthjustice on behalf of Sovereign Iñupiat for a Living Arctic, the Center for Biological Diversity and The Wilderness Society, says the process around the company’s application and its subsequent approval lacked transparency and was rushed. A final decision was issued days after a limited public comment period ended, it says.

The Bureau of Land Management “has pushed this project through without proper analysis or process and without considering the significant flaws in the measures it relies on to justify its approval of the exploration program,” the lawsuit states.

It names as defendants the Bureau of Land Management and its parent agency, the Department of the Interior, along with top officials including Interior Secretary Doug Burgum.

Interior Department spokesperson Alyse Sharpe said the department does not comment on pending litigation.

Dennis Nuss, a spokesperson for ConocoPhillips Alaska, said in an email that the company is confident in the “robustness” of its plan and permits and looks forward to completing its work within the limited winter exploration season.

There has been longstanding debate over how much of the petroleum reserve — which covers an area roughly the size of Indiana — should be open for development. President Donald Trump’s administration has moved to roll back limits on drilling and protections enacted during the Biden administration, and a law passed this year calls for the first lease sales in the reserve since 2019.

The push has been cheered by the state’s Republican congressional delegation and governor, but it raised concerns among environmentalists who caution against the continued embrace of new oil production in the face of climate change. The reserve is home to Teshekpuk Lake, the largest lake in Alaska’s arctic region and third-largest in the state.

Nauri Simmonds, executive director of Sovereign Iñupiat for a Living Arctic, said the proposed exploration program is “not only an assault on caribou and tundra — it is another chapter in the enfoldment of our people into systems designed to fracture us from within.”

“Sovereign Iñupiat for a Living Arctic stands against this approval because our future depends on protecting our homelands, our unity, and our right to live free from the harms of industrial expansion,” Simmonds said in a statement.

The group describes itself online as “an organization of Iñupiat Peoples and community members that believe in a balanced Earth for future generations.”

There are differing views among Alaska Natives, however, over further oil development in places like the petroleum reserve. A group representing many North Slope leaders, Voice of the Arctic Iñupiat, has supported efforts to drill there.

The lawsuit says work under the proposed program could begin “any day” and last until April or May.