The New York Times is seeking e-mail messages between Robert Blair, a top aide to Trump's acting chief of staff, Mick Mulvaney, and Michael Duffey, an official in the White House's Office of Management and Budget. Drew Angerer/Getty

WASHINGTON — The Trump administration disclosed on Friday that there were 20 emails between a top aide to President Donald Trump's acting chief of staff and a colleague at the White House's Office of Management and Budget discussing the freeze of a congressionally mandated military aid package for Ukraine.

But in response to a court order that it swiftly process those pages in response to a Freedom of Information Act, or FOIA, lawsuit filed by The New York Times, the Office of Management and Budget delivered a terse letter saying it would not turn over any of the 40 pages of emails — not even with redactions.

"All 20 documents are being withheld in full," wrote Dionne Hardy, the office's Freedom of Information Act officer.

The Times' information act request sought email messages between Robert Blair, a top aide to Trump's acting chief of staff, Mick Mulvaney, and Michael Duffey, an official in the White House's Office of Management and Budget who was in charge of handling the process for releasing $391 million in weapons and security assistance Congress had appropriated to help Ukraine resist Russian aggression.

In her letter, Hardy cited exemptions to the Freedom of Information Act for correspondence involving the president's staff and internal policy deliberations, suggesting that the disclosure of this material would "inhibit the frank and candid exchange of views that is necessary for effective government decision-making."

David McCraw, a lawyer for The Times, said the newspaper would challenge the blanket withholding of the documents and would ask the judge overseeing the lawsuit, Judge Amy Berman Jackson, to approve an expedited schedule for briefs and arguments given the urgent public interest in learning more about the dispute.

The heart of the accusation against Trump is that he abused his official powers, including withholding a promised White House meeting and congressionally mandated military aid, in an attempt to coerce Ukraine's president into announcing investigations that could deliver personal political benefits to Trump.

In October, the Democratic-led House Intelligence Committee had also subpoenaed the Office of Management and Budget for all Ukraine-related documents, but the White House refused to produce them. It also instructed several key current and former officials with inside knowledge of the episode not to testify.

Sen. Chuck Schumer of New York, the Democratic leader, has portrayed Blair and Duffey as two of the four key witnesses he believes the Senate should call in Trump's impeachment trial, along with Mulvaney and John Bolton, Trump's former national security adviser. Sen. Mitch McConnell, R-Ky., the majority leader, has expressed opposition to calling witnesses and again criticized the House investigation on Friday.

The Trump administration's move to withhold all the emails in full — not even disclosing the dates they were sent, or the shape of paragraphs covered by black lines — is a step beyond its heavy censorship of a related set of emails it released in response to another Freedom of Information Act lawsuit brought by the Center for Public Integrity.

The documents released to the center consisted of about 300 pages of emails between the Office of Management and Budget and the Pentagon about the Ukraine aid package. While the officially released version was heavily redacted — and the center is contesting the censorship in further litigation — the visible portions showed, among other things, that Pentagon officials had worried that holding the funds could be an illegal impoundment.

A report Thursday by the legal policy website Justice Security added further fuel to the controversy by revealing what was under some, but not all, of the deletions. The website said it had been shown some of the emails in unredacted form, including an Aug. 30 message from Duffey to a Pentagon budget official stating that there was "clear direction from POTUS" — an acronym referring to the president of the United States — "to continue to hold" the Ukraine military assistance.

The Times separately reported this week that Blair warned Mulvaney to "expect Congress to become unhinged" if the White House went ahead with the hold on the aid.

Earlier Friday, Schumer went to the Senate floor to praise the reporting by The Times, the Center for Public Integrity and Just Security as an additional reason for the Senate, as part of Trump's trial, to seek documents and testimony that the White House had blocked House impeachment investigators from obtaining.

"What constituted clear direction?" Schumer asked. "Did he get an order from the president, or did someone like Mr. Mulvaney get an order from the president passed on to Mr. Duffey? Was there discussion among officials about covering up for the president in delay of military assistance? These are questions that can only be answered by examination of the documentary evidence and by the testimony of key Trump administration officials under oath in a Senate trial."

At least four collections of emails have now been released, or shared with reporters, detailing correspondence between White House officials and their counterparts at the Office of Management and Budget or the Defense Department.

These exchanges show growing tension between the White House and the Pentagon as Defense Department officials questioned if they would be able to spend all of the military aid before the deadline on Sept. 30.