SIOUX FALLS, S.D. (AP) — One of the insurers that sold health plans through the Affordable Care Act marketplace is reaching out to a group of consumers who may lose coverage because of inconsistencies with the documents that prove their citizenship and immigration status.

Deb Muller with Avera Health Plans says the insurer has been calling and using Facebook to direct its consumers to submit citizenship and immigration documents to the federal government by the Friday deadline.

The federal government has sent letters to about 300 South Dakota residents asking them to show that they're legally living in the U.S. Coverage would end Sept. 30 for those who don't respond.

Nationwide, letters were sent to about 310,000 people. More than half hadn't responded to the request as of Tuesday.

People living in the country illegally aren't eligible for coverage.

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