The head of the U.S. Postal Service acknowledged in a meeting with top Democrats that he instituted new policies restricting overtime and extra mail processing trips, moves that the agency previously downplayed and that postal workers say have caused mail backlogs, according to a letter released Thursday by House Speaker Nancy Pelosi (Calif.) and Senate Minority Leader Charles E. Schumer (N.Y.).

Pelosi and Schumer met with Postmaster General Louis DeJoy, Treasury Secretary Steven Mnuchin and White House Chief of Staff Mark Meadows on Wednesday to discuss reports of those delays, which have reverberated through this year’s primaries by slowing the delivery of absentee ballots.

Internal Postal Service documents obtained by The Washington Post show that postal employees have been barred from working overtime hours and instructed to leave mail behind if it is processed late.

The Postal Service had previously played down the changes both to lawmakers and the press. In a July 22 letter to Sen. Gary Peters (D-Mich.), the top Democrat on the Senate committee responsible for postal oversight, Postal Service general counsel and executive vice president Thomas J. Marshall wrote, “Neither document . . . should be characterized as being ‘official Postal Service memoranda,’ ” and that “neither document originated from Postal Service Headquarters.”

But Pelosi and Schumer wrote Friday that the postmaster general, a former logistics executive and major Republican donor, acknowledged that the Postal Service had implemented the procedures. They called on him to immediately rescind the directives.

“At this meeting, you confirmed that, contrary to certain prior denials and statements minimizing these changes, the Postal Service recently instituted operational changes shortly after you assumed the position of Postmaster General,” the letter states. “These changes include reductions of overtime availability, restrictions on extra mail transportation trips, testing of new mail sorting and delivery policies at hundreds of Post Offices, and the reduction of the number and use of processing equipment at mail processing plants.”

It continues: “We believe these changes, made during the middle of a once-in-a-century pandemic, now threaten the timely delivery of mail — including medicines for seniors, paychecks for workers, and absentee ballots for voters — that is essential to millions of Americans.”

A Postal Service representative did not immediately respond to a request for comment. DeJoy declined to answer questions after the meeting Wednesday.

Mail industry experts said the documents — a slide show and talking points about new mail handling procedures — described a “sea change” in postal policy, re-envisioning an institution older than the nation itself as a for-profit arm of the government. One memo cited U.S. Steel, a onetime industry titan that was slow to adapt to market changes, to illustrate what is at stake.

“This is framing the U.S. Postal Service, a 245-year-old government agency, and comparing it to its competitors that could conceivably go bankrupt,” said Philip Rubio, a professor of history at North Carolina A&T State University and a former postal worker. “Comparing it to U.S. Steel says exactly that ‘We are a business, not service.’ That’s troubling.”

In a statement to The Post on July 13, USPS spokesman David Partenheimer wrote that the agency was “developing a business plan to ensure that we will be financially stable and able to continue to provide reliable, affordable, safe and secure delivery of mail, packages and other communications.”

That plan was not “finalized,” Partenheimer wrote, but would include “new and creative ways for us to fulfill our mission, and we will focus immediately on efficiency and items that we can control, including adherence to the effective operating plans that we have developed.”

On July 30, Partenheimer acknowledged the USPS had “taken immediate steps to better adhere to our existing operating plans” but did not disclose what the steps were.

“Of course we acknowledge that temporary service impacts can occur as we redouble our efforts to conform to the current operating plans, but any such impacts will be monitored and temporary as the root causes of any issues will be addressed as necessary and corrected as appropriate,” he wrote.

Postal workers from across the country said they received the directives about overtime and mail delivery either in “stand-up” talks on shop room floors or in smaller conversations with superiors. The American Postal Workers Union, which represents more than 200,000 USPS employees and retirees, said the contents of the documents were communicated to its members by supervisors nationwide.