WASHINGTON – As many as 3.1 million recipients could lose their food stamp benefits under a proposal unveiled Tuesday.

The Trump administration said the rule was designed to eliminate "loopholes" and save money. But it was immediately assailed by anti-poverty advocates including House Speaker Nancy Pelosi, D-Calif., who called the proposal an "act of staggering callousness."

Under the proposed rule, the U.S. Department of Agriculture's Supplemental Nutrition Assistance Program would no longer provide benefits to families solely because they are enrolled in food assistance programs run by the states where they live.

Over time, some states have expanded eligibility to recipients who would not otherwise qualify for the federal program based on asset or income limitations. Because they are enrolled in the state program, they automatically qualify for SNAP benefits under federal regulations.

USDA officials said the proposed rule would "fix a loophole" that's permitted households to receive assistance "when they clearly don’t need it."

Agency officials said the proposal could save billions in taxpayer funds. Recipients who lose their benefits could reapply and qualify if they met the federal standards for assistance.

“For too long, this loophole has been used to effectively bypass important eligibility guidelines. Too often, states have misused this flexibility without restraint,” Agriculture Secretary Sonny Perdue said in a statement. “The American people expect their government to be fair, efficient, and to have integrity – just as they do in their own homes, businesses, and communities."

About 40 million Americans receive SNAP benefits.

Advocacy groups blasted the move.

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“USDA’s plan to take away flexibility from states to allow people to save funds while working their way out of poverty and still receive SNAP is horrid in four ways," said Joel Berg, CEO of Hunger Free America. "It will make working Americans hungrier. It will make it harder for families to work their way out of poverty. And it is hypocritical since Republicans are denying flexibility to states. We will fight this fiercely.”

Rep. Ilhan Omar, D-Minn., tweeted out a story on the proposal and warned that Trump "does not want you to know about this."

Conservatives have long considered the food stamp program as an example of government waste that needs to be made more efficient.

In December, the administration proposed a rule that would tighten work requirements for SNAP recipients. It would restrict states from exempting work-eligible adults to receive food stamps if they're not seeking employment.

Weeks ago, Congress rejected Republican-sponsored changes to SNAP as part of a $400 billion farm bill.

Rep. Marcia Fudge, D-Ohio, who chairs the House Agriculture Subcommittee that oversees SNAP, criticized Tuesday's proposal as a hypocritical dictate from a party that often preaches states' rights.

"When it comes to putting that rhetoric into practice for SNAP, they take the opposite position," she said.