WASHINGTON ― Two Democrats on the Senate Armed Services Committee are calling on panel leaders to hold a hearing on the Defense Department’s response to COVID-19 and its the role in Operation Warp Speed, a White House-backed effort to create and distribute a vaccine to every American.

Sens. Elizabeth Warren, D-Mass., and Mazie Hirono, D-Hawaii, in a letter Friday to Chairman Jim Inhofe, R-Okla., and ranking member Sen. Jack Reed, D-R.I., asked them to have DoD officials to appear and answer questions about DoD’s pandemic response. Their push comes as National Public Radio has reported that Operation Warp Speed’s contracting through non-traditional “other-transaction authorities” is shielding it from public-disclosure rules.

The lawmakers wrote that the project’s $6 billion in awards through a defense contract management firm, Advanced Technologies International, Inc., “bypasses regulatory requirements and limits transparency, raising numerous questions and ethical concerns,” and that Congress should look into the issue. Their letter was obtained by Defense News.

Despite skepticism from inside the military about Operation Warp Speed’s bold goal to have 300 million safe and effective doses, with the initial doses in January 2021, President Donald Trump are other Republicans are touting the effort in reelection campaigns. Trump mentioned it during the final presidential debate last week.

Congress has so far allotted $10 billion to the public-private partnership, which is between private firms several federal agencies, including the Department of Health and Human Services, Centers for Disease Control and Prevention, the Food and Drug Administration, the National Institutes of Health and the Biomedical Advanced Research and Development Authority.

On Friday, officials with the effort said there are six vaccine candidates that must be evaluated in clinical trials, and that while the U.S. military will lend its logistics experience to the effort, its personnel won’t be administering any of the COVID-19 vaccines.

In their letter, Warren and Hirono noted that 60 of the 90 members of Operation Warp Speed are with the military (as first reported by the publication STAT), and they complained DoD/HHS telebriefing on the operation for members and staff did not include a DoD official to brief members or answer questions. (Army Gen. Gus Perna, the former chief of Army Materiel Command, leads the initiative.)

The lawmakers also pointed to criticism that the “overrepresentation” of military personnel may come at the expense of public health officials who have greater expertise.

“Public health agencies such as FDA and CDC are surprisingly underrepresented with just a few members of each organization present in OWS’s reported organizational structure,” they said. “DoD’s outsized involvement in this public health crisis is a stark departure from similar operations used to combat past public health crises such as H1N1 and the outbreak of Ebola.”

As the Senate Health, Education, Labor, and Pensions Committee has held two hearings with administration officials from the FDA, CDC, and other public health agencies, they said, the Senate Armed Services Committee should hear from DoD officials.

Spokespeople for Inhofe and Reed did not respond to requests for comment.