WASHINGTON — Trump administration rules that could deny green cards to immigrants who use Medicaid, food stamps, housing vouchers or other forms of public assistance are going into effect, potentially making it more difficult for some to become U.S. citizens.

Federal law already requires those seeking green cards and legal status to prove they will not be a burden to the United States, or what’s called a “public charge,” but the new rules, made public today, detail a broader range of programs that could disqualify them.

U.S. Citizenship and Immigration Services officers will now weigh public assistance along with other factors such as education, household income and health to determine whether to grant legal status.

Much of President Donald Trump’s effort to crack down on illegal immigration has been in the spotlight, but the rule change is one of the most aggressive efforts to restrict legal immigration. It’s part of a push to move the U.S. to a system that focuses on immigrants’ skills instead of emphasizing the reunification of families, as it has done.

The rules will take effect in mid-October. They don’t apply to U.S. citizens, even if the U.S. citizen is related to an immigrant who is subject to them.

The acting director of Citizenship and Immigration Services, Ken Cuccinelli, said the rule change fits with the Republican president’s message.

“We want to see people coming to this country who are self-sufficient,” Cuccinelli said. “That’s a core principle of the American Dream. It’s deeply embedded in our history, and particularly our history related to legal immigration.”

Immigrants make up a small percentage of those who get public benefits. In fact, many are ineligible for public benefits because of their immigration status.

But advocates worry the rules will scare immigrants into not asking for help. And they are concerned the rules give too broad an authority to decide whether someone is likely to need public assistance at any time, giving immigration officials the ability to deny legal status to more people.

On average, 544,000 people apply annually for green cards, with about 382,000 falling into categories that would be subject to this review, according to the government.

Guidelines in use since 1999 referred to a public charge as someone primarily dependent on cash assistance, income maintenance or government support for long-term institutionalization.