Two Republican committee chairmen are threatening to subpoena Obama administration officials if the Department of Health and Human Services doesn't provide information about how it's funding an optional health program set up under Obamacare.

HHS Secretary Sylvia Burwell needs to explain how her agency dispersed funds for the Basic Health Program, Ways and Means Chairman Kevin Brady, R-Texas, and Energy and Commerce Chairman Fred Upton, R-Mich., argued in a letter to the agency. The Basic Health Program is an optional plan states can use to cover low-income residents by contracting with plans outside the new insurance marketplaces.

The program was created, but not funded, under the 2010 Affordable Care Act. While the Republican-led Congress has refused to provide money for it, the Obama administration has provided funds to Minnesota and other states to set it up.

Last summer, Brady and Upton asked HHS for documents explaining where the agency is getting the funds. In a letter sent to the agency Friday, they said HHS has not cooperated with their investigation, and threatened to "consider the use of the compulsory process" if it doesn't hand over the documents by Jan. 28.

"Once again, HHS has failed to respond to the committees' request," Brady and Upton wrote. "Your delay in producing this material to the committee has frustrated the committees' investigation, and raises serious concerns about your commitment to congressional oversight. We urge you to comply fully with this request by immediately producing all responsive documents to the Committees without redactions."