WASHINGTON – Should the Pentagon be allowed to authorize the use of unapproved drugs and medical devices on an emergency basis for combat soldiers?

That question has sparked a furious battle this week among some of Washington's biggest power players, with the Defense Department and its congressional advocates on one side and the Food and Drug Administration and the health committees on the other.

The Capitol Hill clash was set off by a provision in the annual defense authorization bill.

The provision would allow the secretary of defense to authorize the emergency use of drugs and devices that have not been approved by the Food and Drug Administration. The permission would apply to military personnel who are outside the United States. The purpose, the bill says, would be "to reduce the number of deaths or the severity of harm to members of the armed forces . . . caused by a risk or agent of war."

Under current law, the FDA has the sole authority to make decisions on medical products, including during an emergency. The Defense Department can ask the FDA to grant an emergency authorization to use unapproved drugs and devices if there's a threat of a chemical, biological, radiological or nuclear agent.

The FDA and leaders of congressional health committees say that giving the Pentagon the authority to decide whether to use unapproved drugs and devices could expose soldiers to dangerous products. Members of the defense panels and the Pentagon argue that the measure would save lives by ensuring that soldiers in combat situations get cutting-edge treatments.

Capitol Hill talks to resolve the dispute are now underway. The FDA and the leaders of the health committees favor a different approach that would create an expedited process for the Pentagon's emergency-use requests. That would be similar to the FDA's "breakthrough" designation for promising drugs for serious or life-threatening conditions. If lawmakers agree on new language, it could be offered as an amendment to the defense bill or in future legislation. The House-Senate conference report, filed Wednesday, which includes the provision to allow unapproved drugs and devices, could be voted on by the House as soon as next week.

Regardless of the outcome of the talks, the disagreement, first reported by Politico, puts on public display an internal rift within the administration and in Republican congressional ranks.

FDA Commissioner Scott Gottlieb, in remarks at an event on the opioid epidemic sponsored by the Hill on Tuesday, expressed unhappiness with the defense-bill language, saying medical-product approvals should be kept under his agency's control.

"We think we provide a level of oversight that helps ensure the safety of products, helps follow-up to make sure that if there are adverse events we're monitoring them, we're collecting that information," he said.

Navy Cmdr. Gary Ross, a Pentagon spokesman, said that the Defense Department, if given the emergency authorization, would exercise caution.

"Patient safety is at the heart of everything we do," he said. "If DOD is given this authority, we would work closely with our FDA colleagues to ensure lifesaving treatments are fielded quickly while protecting patient safety."

Under the defense bill's language, the Pentagon would be required to create a panel of outside experts to recommend when an unapproved product should be used, and defense officials would have to consult with the FDA – but would not have to follow its advice.

Congressional supporters of the provision say lawmakers are frustrated over what they see as FDA delays in approving freeze-dried plasma, a dehydrated form of plasma that is intended to be quickly reconstituted and given to soldiers during military operations. Such plasma is being used by a small number of U.S. troops under limited permission from FDA, and by some U.S. allies.

"Members feel like if the secretary of defense thinks this is a life-and-death situation and there's something on the market internationally that can make a difference but hasn't been approved by the FDA, there ought to be a way to short-circuit the process and get it on the battlefield as soon as we can," a House aide said.

Gottlieb said that the FDA could approve the plasma as soon as 2018, more quickly than if the Pentagon had to develop its own review process.

The Pentagon provision has strong support among defense lawmakers of both parties, including Senate Armed Services Committee Chairman John McCain (R., Ariz.); ranking member Sen. Jack Reed (D., R.I.); House Armed Services Committee Chairman Mac Thornberry (R., Texas), and ranking member Rep. Adam Smith (D., Wash.).

In a letter to those lawmakers on Thursday, five former FDA commissioners who served in both Democratic and Republican administrations — Margaret Hamburg, Jane Hanney, David Kessler, Mark McClellan and Andrew von Eschenbach — denounced the provision and said it "likely increases the risks for our military personnel."

Lawmakers who support the FDA position include Sen. Lamar Alexander (R., Tenn.), chairman of the Health, Education, Labor and Pensions Committee; Sen. Richard Burr (R., N.C.), chairman of the Intelligence Committee; and Rep. Greg Walden (R., Ore.), chairman of the Energy and Commerce Committee.

Michael Carome, director of Public Citizen's Health Research Group, said it is a "horrible idea" for the Pentagon to get authorization to use unapproved materials on troops. "It will endanger the FDA's authority and endanger the soldiers," he said.

Some critics pointed to the Pentagon's past failures to protect soldiers from potentially dangerous experimentation. For example, for many years during the last century, thousands of troops were exposed to mustard gas, hallucinogens and other dangerous substances without their knowledge.