(WASHINGTON) — The House is set to vote on a bill related to the ailing U.S. Postal Service in an unusual Saturday session amid an ongoing political controversy over mail-in voting.

The chamber will vote on the “Delivering for America Act,” which would provide $25 billion in new funding for the agency, and it would explicitly prohibit any operational changes made this year. The bill would also require that all official election mail be treated as “first-class mail,” prohibit the removal of mail sorting machines and mailboxes, and reverse any already implemented changes that could delay mail delivery.

The House is expected to pass the bill along party lines after Republicans announced earlier in the week that they would not support the bill. The measure is not expected to be taken up by the Senate.

In a letter addressed to colleagues late Thursday, House Speaker Nancy Pelosi suggested that the House will vote only on the postal service bill this weekend and nothing else related to coronavirus relief, despite a strong push from Democrats to vote on other coronavirus relief legislation.

More than 100 Democrats signed a letter urging Pelosi and leadership to consider forcing a vote on a coronavirus relief bill, specifically an extension of the federal unemployment insurance benefits.

“As we review suggestions for our agenda, I continue to appreciate the thoughtfulness and commitment of our Members to America’s working families. The ideas Members have put forth have been excellent and I have shared them with the Chairs of the committees of jurisdiction to be part of our legislative agenda,” Pelosi said in the letter.

“However, we must consider their timing and strategic value. They cannot come at the expense of addressing the priorities of the Heroes Act — particularly support for our heroes in state and local government and education, who are in crisis,” she said.

Republicans have blasted Democrats for voting on the USPS bill and have referred to the measure as a “conspiracy theory.”

Facing lawmakers on Friday for the first time as head of the U.S. Postal Service, embattled Postmaster General Louis DeJoy strongly disputed allegations that he’s making changes to the agency’s operations to help boost President Donald Trump’s reelection in November, calling such claims “outrageous.”

Postmaster General Louis DeJoy responds to questions during a virtual hearing held by the US Senate Committee on Homeland Security & Governmental Affairs in Washington, Aug. 21, 2020.

Instead, DeJoy, a former logistics executive and longtime Republican financier, framed the changes as necessary to reverse years of significant financial losses incurred by a continuing drop in mail volume.

While he refused to undo cost-saving measures that have already been implemented as Democrats have demanded, DeJoy vowed that the Postal Service is “fully capable” of “securely” handling millions of ballots and delivering them on time, as pandemic-wary voters look for a safer way to pick their next president.

The internal changes at the heart of DeJoy’s testimony coincided weeks earlier with a full-on attack on “mail-in voting” from. Trump, sparking the allegations of improper political influence.

DeJoy will testify in the House on Monday, where he is expected to be grilled by Democrats.

ABC News’ Mike Levine contributed to this report.

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