WASHINGTON – President Donald Trump's administration issued a new rule Monday that would enable officials to deny green cards to migrants if they believe the recipients will receive public benefits like food stamps, Medicaid, or housing vouchers.

The rule, in the works for months, is the administration's latest effort to reduce legal immigration – despite Trump's focus on illegal immigration. Officials said the move is intended to ensure those approved for legal residency support themselves.

“To protect benefits for American citizens, immigrants must be financially self-sufficient," Trump said in a statement.

The rule, which would take effect Oct. 15, allows customs and immigration officers to consider public assistance in deciding whether to grant legal assistance, along with other facts like health, education, and household income. In addition to considering whether an applicant currently receives benefits, they will also determine whether there is a likelihood that person will do in the future.

Administration officials said they had no estimates of how many people could be affected.

Critics have accused the Trump administration of seeking to reduce the number of legal immigrants through what the government calls a "public charge" rule. They also accused the administration of targeting poor people and legal immigrants who are seeking to gain a foothold in the U.S. economy.

In a tweet, the National Immigration Law Center described the proposal as "a race motivated wealth test on immigrant families seeking a healthy, stable future in the US. If this goes into effect, it would have a devastating impact on millions. We WILL fight back. Stay tuned for updates."

Ken Cuccinelli, acting director of U.S. Citizenship and Immigration Services, said the purpose of the rule is to promote "self-sufficiency" among the immigrant population.

"Through the public charge rule, President Trump's administration is re-enforcing the ideals of self-sufficiency and personal responsibility, ensuring that immigrants are able to support themselves and become successful here in America," he said.

Asked about the impact on the poor, Cuccinelli said: "We certainly expect people of any income to be able to stand on their own two feet.”

Earlier this year, the Trump administration instructed agencies to enforce a 23-year-old law that requires sponsors of green card holders to reimburse the government for welfare benefits.

Administration officials noted that the rule is required by an immigration law signed by President Bill Clinton in 1996. The U.S. grants green cards to roughly 1 million foreigners each year.

The current definition of a public charge includes someone who is "primarily dependent" on government assistance. That means receiving cash assistance that makes up more than half of their income, or receiving long-term medical care "at government expense."

The new definition, which has not yet gone into effect, would dramatically expand that definition to include any immigrant who receives even small amounts of government aid. That includes "non-cash" benefits, such as use of the Supplemental Nutrition Assistance Program (known as food stamps), Medicaid in non-emergency situations, and Section 8 housing and rental assistance.