The Trump administration is set to tighten work requirements for recipients of federal food aid, potentially rendering hundreds of thousands of people ineligible for the program by mid-2020.

The administration said Wednesday that it had completed a new rule curbing states’ ability to shield adults without dependents from federal work requirements tied to receiving assistance through the program formerly administered via food stamps. Officials say the rule, which takes effect April 1, 2020, will save the government billions of dollars and encourage more people to work at a time when jobless rates are near a 50-year low.

The rule is the first to take effect among several Trump administration proposals to restrict access to the Supplemental Nutrition Assistance Program, or SNAP, which provides aid to 36.4 million people. The U.S. Department of Agriculture, which oversees the program, separately has proposed tightening eligibility requirements for low-income households and changing how utility costs factor into eligibility.

“This rule lays the groundwork for the expectation that able-bodied Americans reenter the workforce where there are currently more job openings than people to fill them,” said USDA Secretary Sonny Perdue.

Critics, including Democratic members of Congress, have said the Trump administration’s efforts deepen hardships for poor families and circumvent congressional authority over government assistance programs.