BILLINGS, Mont. — A U.S. judge temporarily blocked the Trump administration from easing rules on mining, drilling and grazing across millions of acres in seven Western states, saying such activities left unchecked were likely to harm a struggling bird species.

The ground-dwelling greater sage grouse is at the center of a bitter conflict between the administration and conservationists involving how much of the West's expansive public lands should be opened to development.

The temporary restraining order issued Wednesday by a judge in Boise, Idaho, means the administration for now must fall back to more stringent rules adopted under former President Barack Obama.

Sage grouse have been in decline for decades due to habitat loss and other factors, and their numbers dropped sharply again this year across much of an 11-state range.

The Trump land-use plans finalized in March had removed the most protective sage grouse habitat designations. Administration officials also dropped requirements to prioritize leasing for oil and gas outside sage grouse habitat and allowed more waivers for drilling.

U.S. District Judge B. Lynn Winmill did not say in his order when he will make a final decision in the case.

The Trump rule changes affect public land in Idaho, Wyoming, Colorado, Utah, Nevada, California and Oregon. Sage grouse territory in Montana, Washington and the Dakotas was not impacted.

U.S. Interior Department spokesman Nick Goodwin noted that the changes had followed coordination with officials in the affected states, including some with Democratic governors.

"The previous plans from 2015 ignored the individual needs of states," Goodwin said. "The common-sense amendments made by the department are legally sound and struck the appropriate balance in effectively managing these important public lands."

Goodwin declined to say if the administration plans to appeal the ruling Wednesday.

Michael Saul, an attorney for one of the environmental groups involved in the case, said the ruling blocked a "despicable and illegal plan" to open every acre of federally managed grouse habitat to drilling.

"This ruling gives the sage grouse a better shot at avoiding extinction," Saul said in a statement.

The case before Winmill dates to 2016, when environmental groups sued the Obama administration over rules that they described as insufficient to protect grouse from heading toward extinction.

The groups added to their original lawsuit when the rules were further weakened as part of the Trump administration's campaign to increase U.S. energy production.

Kathleen Sgamma with the Western Energy Alliance, an oil industry lobbying group, said Winmill's ruling was not a surprise because the judge is favored by environmental groups for his his pro-conservation rulings.

She predicted the effect on the ground would be limited because under a prior court order the Trump administration already was following Obama-era rules for the issuing of energy leases to companies.

Sgamma said the environmental groups involved in the case "will never be satisfied until all oil and natural gas leasing is stopped."