OKLAHOMA CITY (AP) — The U.S. government wants a portion of Oklahoma's $270 million settlement with Purdue Pharma that stemmed from the state's ongoing lawsuit against opioid makers.

The U.S. Centers for Medicare and Medicaid Services wrote to the head of Oklahoma's Medicaid agency that it has determined the federal government is entitled to part of Oklahoma's proceeds.

The June 12 letter from CMS' regional director Bill Brooks also seeks detailed information from the Oklahoma Health Care Authority and warns that failure to return a portion of the settlement money could result in the withholding of federal funds. Medicaid is jointly funded by the federal government and states.

Details of the letter were first reported Thursday by The Washington Post.