WASHINGTON — The Pentagon is objecting to a Republican proposal in a defense policy bill that would bar the Fish and Wildlife Service from using the Endangered Species Act to protect two chicken-like birds in the western half of the U.S.

The Defense Department says in a position paper made public Wednesday that the environmental measure inserted by House Republicans is unnecessary. The House-approved language would block endangered-species listing for the sage grouse and lesser-prairie chicken, which roam more than a dozen states west of the Mississippi River.

The birds have become flashpoints in a legal and political battle over whether they warrant federal protection that hinders mining, logging and other economic development in states from Kansas to California.

The Pentagon says in a one-paragraph statement that the GOP provision "is not necessary to protect military testing and training." The department "urges its exclusion" from the defense bill being negotiated by House and Senate leaders, the statement said.

The Associated Press obtained a copy of the statement and confirmed its authenticity.

Lucian Niemeyer, assistant secretary of defense for energy, installations and environment, said Wednesday that officials appreciate "the continued strong support from Congress to protect military readiness, and the ability to fully use all of our test and training ranges."

But Niemeyer said military installations are "not experiencing significant mission impacts related to the management" of the sage grouse, lesser-prairie chicken or the American burying beetle, another threatened species targeted by the GOP bill. The burying beetle was once found across the country but has dwindled to less than 10 percent of its historic range.

"Legislation at this time prohibiting the listing of these species may have the unintended consequence of undermining the ongoing working relationships and initiatives that DOD has with our federal, state and private partners as it relates to balancing wildlife conservation and sustaining our readiness capabilities," Niemeyer said in a statement.

Utah Rep. Rob Bishop inserted the endangered-species language into the defense policy bill, arguing that federal conservation efforts for the imperiled birds and the beetle undermine military training and readiness.

Retired Major Gen. Paul Eaton, managing director of Vet Voice Foundation, an advocacy group that supports environmental causes, called the GOP rider "a shameful ploy" to undermine important public lands and wildlife protections.

"Congressional leadership must put a stop to this effort and ensure that members of Congress do not hold hostage the National Defense Authorization Act over a rider that has nothing to do with the military," Eaton said.

The GOP rider comes amid an effort by Bishop and other Republicans to advance legislation rolling back the Endangered Species Act. Republicans say the landmark 45-year-old law hinders a host of economic activities important for jobs while doing little to restore threatened species.

Democrats and environmental groups say the law has played a crucial role in protecting imperiled species such as the bald eagle, California condor, brown pelican and Florida manatee from extinction.