The Trump administration is expected to issue a proposal in the coming weeks that would make it harder for legal immigrants to become citizens or get green cards if they have ever used a range of popular public welfare programs, NBC News reported. Obamacare could be among those programs, sources with knowledge of the plan said.

The move would not need Congressional approval, and is part of White House senior adviser Stephen Miller's plan to limit the number of migrants who obtain legal status in the U.S. each year. It would be the biggest change to the legal immigration system in decades, according to immigration lawyers, advocates, and public health researchers. They estimate more than 20 million immigrants could be affected.

Details of the rule-making proposal are still being finalized. However, based on a recent draft seen last week and described to NBC News, immigrants living legally in the U.S. who have ever used or whose household members have ever used Obamacare, children's health insurance, food stamps and other benefits could be hindered from obtaining legal status in the U.S.

A spokeswoman for the Department of Homeland Security said, "The administration is committed to enforcing existing immigration law, which is clearly intended to protect the American taxpayer by ensuring that foreign nationals seeking to enter or remain in the U.S are self-sufficient. Any proposed changes would ensure that the government takes the responsibility of being good stewards of taxpayer funds seriously and adjudicates immigration benefit requests in accordance with the law."

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