By Jeremy Herb, CNN

(CNN) -- Postmaster General Louis DeJoy defended the US Postal Service's mail service Monday, arguing that the recent delays in service were temporary and would not impact the ability to deliver mail-in ballots in November.

DeJoy faced pointed questions from House Democrats on Monday over the changes he's put in place that have led to delays in mail delivery, which they warn put at risk the Postal Service's handling of mail-in ballots in November.

DeJoy acknowledged that a "deterioration in service" had occurred following changes to mail trucks taking additional trips, but he said the USPS was already seeing a bounce-back. And he argued that other changes, like the removal of mail-processing machines, were already happening before he took over in June.

"There are many inaccuracies about my actions that I wish to again correct," DeJoy said. "First, I did not direct the removal of blue collection boxes or the removal of mail processing equipment. Second, I did not direct the cutback on hours at any of our postal offices, and finally I did not direct the elimination or any cutback in overtime. I did, however, suspend these practices to remove any misperceptions about our commitment to delivering the nation's election mail."

DeJoy testified before the GOP-led Senate Homeland Security and Governmental Affairs Committee on Friday, where he was pressed by Democrats and Republicans alike about delays in the mail that lawmakers have heard about across the country. He faced a far more hostile reception in the House, where 90 Democrats called for DeJoy's removal last week, including many committee members.

"This is just a disaster for the people who need their mail," said House Oversight Chairwoman Carolyn Maloney, a New York Democrat.

Maloney accused DeJoy of withholding information from Congress about USPS operations, threatening a subpoena if he did not comply with the panel's requests. The committee released on Saturday an internal USPS slide presentation prepared for the Postmaster General last week that showed a significant reduction in service since the beginning of July -- after DeJoy took over.

Maloney charged that if DeJoy was the CEO of a company with a "plummeting record" like he did, the CEO would be removed.

"That's an unfair accusation," DeJoy shot back.

Democrats also want to know more about what role Treasury Secretary Steve Mnuchin has played, who was briefed by the Board of Governors on DeJoy's appointment and negotiated a $10 billion loan that gave Treasury access to USPS contacts with major customers like Amazon. The House on Saturday approved a bill to give USPS an additional $25 billion.

USPS Board of Governors Chairman Mike Duncan, who is testifying alongside DeJoy, defended the board's appointment of DeJoy, saying in his prepared remarks DeJoy was unanimously selected following a rigorous selection process.

"There must be dramatic changes if the Postal Service is to succeed. Mr. DeJoy was selected to be that transformational leader, who can help strengthen the Postal Service for the long term," Duncan said. "He is the fifth Postmaster General since 1971 to join the institution from the private sector, and we believe that private sector experience is an asset in identifying ways to improve the Postal Service."

Trump has continued to rail on mail-in voting, falsely claiming that it will lead to significant fraud and will lead to a "rigged" election. DeJoy stated his support for mail-in voting at Friday's hearing, saying that the USPS "will deliver every ballot and process every ballot in time that it receives."

Republicans have accused Democrats of manufacturing a political crisis with the mail to help the party politically, arguing the Postal Service's fiscal woes are a long-running problem and DeJoy is trying to address them. Rep. James Comer of Kentucky, the top Republican on the Oversight Committee, charged that Democrats had "fabricated a baseless conspiracy theory" in his opening statement Monday.

"Is the postmaster general sabotaging the election by removing blue postal boxes and mail sorting machines? No, the Postal Service has more than adequate capacity to handle the vote-by-mail," Comer said. "If everybody in the US requests and sends their ballots via mail, that's still less than one day's average volume."

House Speaker Nancy Pelosi called lawmakers back to Washington for a rare Saturday session to approve the legislation that provided the Postal Service with a $25 billion boost, along with suspending the changes DeJoy has put in place.

The bill passed 257-150, with more than two dozen Republicans joining with Democrats in favor. The White House has issued a veto threat, and the measure is not expected to be taken up by the Republican-led Senate.

"It is also necessary for us to have this legislation because in my conversations with the postmaster general, which were most unsatisfactory, he said he had no intention of restoring the post office boxes that were removed, no intention of restoring the sorting machinery in the Postal Services and other infrastructure very essential to keeping the mail on time," Pelosi said at a news conference Saturday.

Democrats said following Friday's hearing they were unsatisfied with the answers they heard from DeJoy, and they planned to press him further. While DeJoy pledged he would hold off on making changes until after the election, Democrats have expressed skepticism.

"Frankly, no one really believes him," said Senate Minority Leader Chuck Schumer, a Democrat from New York who announced on Sunday that a subcommittee on the USPS Board of Governors would investigate policy changes ahead of the election.

This story has been updated with additional developments Monday.