President Donald Trump blasted Republicans Wednesday on Twitter -- tagging Senate Majority Leader Mitch McConnell in a rare move -- for "allowing the Democrats to have ridiculous Post Office hearings on Saturday & Monday, just before and during our Convention" as Democrats revisit questions surrounding the selection process of Trump's controversial postmaster pick.
Under mounting concerns with mail-in voting and increased scrutiny in recent weeks for enacting a series of measures meant to streamline the Postal Service, Postmaster General Louis DeJoy has agreed to testify at a GOP-controlled Senate hearing on Friday and a Democratic House hearing on Monday -- the first day of the Republican National Convention.
MORE: As states threaten lawsuits, postmaster general suspends mail-handling changes until after election"Let them hold them NOW (during their Convention) or after our Convention is over. Always playing right into their hands," Trump said in a tweet, tagging McConnell.
However, it is Sen. Ron Johnson, R-Wisc., who chairs the Senate Homeland Security and Governmental Affairs Committee, which called on DeJoy to testify after Democrats demanded he do so.
In a statement Tuesday, Johnson said DeJoy "should have an opportunity to describe those realities before going before a hostile House committee determined to conduct a show trial."
Ahead of the two blockbuster hearings, DeJoy announced Tuesday he will suspend several of the cost-cutting initiatives he made until after the election in an effort "to avoid even the appearance of any impact on election mail."
Though intended to relieve pressure, the announcement has provoked more transparency questions among Democrats seeking to investigate not only DeJoy's actions as postmaster but the decision to put him in the position.
House Speaker Nancy Pelosi said she spoke with DeJoy Wednesday morning and bluntly told him his announcement to temporarily pause operational changes at the Postal Service is "not a solution and is misleading."
She said in a statement on their call that DeJoy "frankly admitted that he had no intention of replacing the sorting machines, blue mailboxes and other key mail infrastructure that have been removed and that plans for adequate overtime, which is critical for the timely delivery of mail, are not in the works."
MORE: Postmaster general agrees to testify before Senate, House lawmakers amid mail-in voting firestormIn a letter to DeJoy Wednesday, Senate Minority Leader Chuck Schumer outlined specific questions he hopes DeJoy will answer after warning DeJoy over the phone Tuesday of him imminent request for specific, written information about which policies he intended to suspend.
Questions include whether election mail will be treated as first class mail and whether blue mail boxes and mail sorting equipment that has already been removed will be returned.
Earlier Wednesday, Schumer also sent a letter to the Chairman of the United States Postal Service Board of Directors Robert Duncan, re-upping his ask for disclosure of information related to the selection of DeJoy, a longtime Republican donor.
His letter to Duncan outlines confidentiality claims made by the Postal Service and the search firm used to select DeJoy, called Russell Reynolds, that Schumer said have hindered congressional oversight of the Postal Service and calls for Russell Reynolds to be released from the non-disclosure agreement that they've said prohibits them from disclosing information on DeJoy's selection to Congress.
It also re-ups concerns Schumer has expressed about the role that Treasury Secretary Steve Mnuchin may have played in DeJoy's selection.
"The Board's response was silent on the role White House and Treasury Department officials played in the search process. Recent reports have raised President Trump's personal obsession with and grievances against the Postal Service and his desire to replace the former Postmaster," Schumer wrote. "As part of my inquiry, my office learned of the role Treasury Secretary Steven Mnuchin had with Postal Board of Governors, including through meetings with individual Governors as well as phone calls with groups of Governors, which has not been previously disclosed by the Board."
Despite Democrats' concerns about mail-in voting millions of American are relying on amid the pandemic, Trump continued to attack the practice Wednesday, tweeting "IF YOU CAN PROTEST IN PERSON, YOU CAN VOTE IN PERSON" -- less than 24 hours ago his Facebook page posted a video of him singing his absentee ballot to Facebook.
His persistence comes as more than 20 state attorneys general are forging ahead with at least two lawsuits against the Trump administration and the U.S. Postal Service, among others, arguing the service broke the law by making operational changes without seeking approval from the Postal Regulatory Commission and that the changes impede on states' abilities to run free and fair elections.
Pelosi said on Tuesday the House of Representatives will also go ahead with a vote on Saturday on a bill designed to reverse those operational changes DeJoy says he's now suspending and provide $25 billion in support.
At a briefing Tuesday, White House press secretary Kayleigh McEnany said it is a “farce” that there’s an emergency with the Postal Service and accused Pelosi and Democrats of pursuing a “manufactured crisis” by coming back into session over the weekend for the issue.
“This notion that there's this emergency for which Nancy Pelosi needs to rush back to Capitol Hill to solve is a farce,” McEnany said. “It is false. The real thing that's happening here is Nancy Pelosi is feeling pressure from her members, from her constituents, because she's not delivered relief for Americans.”
She said the White House is open to additional funding for the Postal Service and would not put a cap on its number, adding they would be willing to consider the $25 billion proposed by Democrats.
While McEnany railed against what she argued is an unnecessary emergency session this weekend in the House, she also called Pelosi “reckless” and said the White House is waiting for her to “get back and do her job” in reaching a deal for direct payments for Americans, seeking to place full blame on the Democrats for the impasse between the two parties.
ABC News' Elizabeth Thomas contributed to this report.