(CNN) A federal district court judge handed the Trump administration another defeat in its attempt to allow states to impose work requirements in Medicaid, which has caused 18,000 people to lose coverage so far.

In two closely watched cases, US District Court Judge James Boasberg Wednesday voided the administration's approvals of requests by Kentucky and Arkansas to mandate that low-income people work for benefits and kicked the matter back to the Department of Health & Human Services for further review. Boasberg also suspended the program in Arkansas, which began in June.

In both cases, the approvals did not address how the requests would align with Medicaid's core objective of providing Medicaid coverage to the needy, the judge said. However, Boasberg also said that it's not impossible for the agency to justify its approvals, but it has yet to do so.

The Centers for Medicare & Medicaid Services, which has granted work requirement requests from nine states and is considering several more, was not deterred by the ruling.

"We will continue to defend our efforts to give states greater flexibility to help low income Americans rise out of poverty," said Seema Verma, the agency's administrator. "We believe, as have numerous past administrations, that states are the laboratories of democracy and we will vigorously support their innovative, state-driven efforts to develop and test reforms that will advance the objectives of the Medicaid program."

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