WASHINGTON (AP) — Calling it "unserious and unacceptable," House Democratic leader Hakeem Jeffries rejected on Monday a proposal from Speaker Mike Johnson that links continued government funding for six months with a measure to require proof of citizenship when registering to vote.

The response frames the spending battle to come over the next weeks as lawmakers work to reach consensus on a short-term spending bill that would prevent a partial government shutdown when the new fiscal year begins Oct. 1. Lawmakers hope to avoid a shutdown just weeks before voters go to the polls.

Johnson is punting the final decisions on full-year spending into next year when a new president and Congress take over. He's doing so at the urging of members within his conference who believe that Republicans will be in a better position next year to secure the funding and policy priorities they want.

But Jeffries said the appropriations process should be wrapped up before the end of the current calendar year, and the short-term measure should reflect that. It also needs to be free of "partisan policy changes," Jeffries said.

"There is no other viable path forward that protects the health, safety and economic well-being of hardworking American taxpayers," Jeffries wrote in a letter to House Democrats released Monday.

Lawmakers are returning to Washington this week following a traditional August recess spent mostly in their home states and districts. They are not close to completing work on the dozen annual appropriations bills that will fund the agencies during the next fiscal year, so they'll need to approve a stopgap measure.

The House bill including the proof of citizenship mandate for voter registration complicates the effort. The voter registration measure is popular with House Republicans. The House Freedom Caucus, which generally includes the chamber's most conservative members, called for it to be attached to the spending bill.

Republicans say that requiring proof of citizenship would ensure that U.S. elections are only for American citizens, improving confidence in the nation's federal election system, something that former President Donald Trump has sought to undermine over the years.

When the House Republican proposal was unveiled on Friday, Johnson called it a critically important step to keep the federal government funded and secure the federal election process.

"Congress has a responsibility to do both, and we must ensure that only American citizens can decide American elections," Johnson said.

Opponents say it is already against the law for noncitizens to vote in federal elections and that the document requirements would disenfranchise millions of people who do not have the necessary documents readily available when they get a chance to register.

Trump and other Republicans have revved up their complaints about the issue of noncitizens voting with the influx of migrants across the U.S.-Mexico border under President Joe Biden's administration. They are contending Democrats let them in to add them to the voter rolls. But the available evidence shows that noncitizen voting in federal elections is incredibly rare.

Senate Democrats have also come out against Johnson's proposal. And Biden administration officials have also weighed in against the bill. Defense Secretary Lloyd Austin warned that long-term continuing resolutions, such as the current one to be voted on in the House this week, harm military readiness.

Austin said in a letter to the chairs and ranking members of the House and Senate Appropriations Committees that, if passed, the bill would mark the second year in a row and the seventh time in the past 15 years that the department is delayed in moving forward with some critical priorities.

"These actions subject Service members and their families to unnecessary stress, empower our adversaries, misalign billions of dollars, damage our readiness, and impede our ability to react to emergent events," Austin wrote.