The Biden administration this week sent letters to state health officials, warning that many are failing to meet federal requirements about determining Medicaid coverage for tens of millions of people in the wake of the pandemic public health emergency.

The Centers for Medicare and Medicaid Services (CMS) has expressed concern for months that many states are rushing through the process, resulting in people losing coverage for “procedural” reasons even though they may still be eligible.

But the agency has so far been reluctant to take formal action against states that violate federal rules.

The CMS on Wednesday made public letters it sent to all 50 states, flagging three key areas of concern: high rates of people losing Medicaid because of paperwork problems, long call center wait times and call abandonment rates, and slow application processing.

The letters were based on data reported by states in May only, so the numbers have changed since then, and not every state is reporting.

While much of the attention has been on the Republican-led states rushing through the process, the letters cited 36 states for at least one problem, including blue states.

Five states — Alaska, Florida, Montana, New Mexico and Rhode Island — were cited for all three issues. For example, Alaska reported that 28 percent of renewals due in May were terminated for procedural reasons.