Leaked emails reveal Pentagon officials were worried that Donald Trump directing a military aid freeze to Ukraine was unlawful.

National security specialist news website JustSecurity.org was passed the contents of 300 pages of previously-redacted emails, with the leaked material showing growing concern from Defense Department officials that the freeze would violate the Impoundment Control Act.

It included a message from an OMB - Office of Management and Budget - official who said Donald Trump had given 'clear direction… to hold' military aid from Ukraine.

The emails were initially released in two batches last month on December 12 and 21, but the Justice Department decided to black-out several sections, either partially or fully.

Senator Chuck Schumer reacted to the content of the emails on Twitter Thursday.

'The newly-revealed unredacted emails are a devastating blow to Senator McConnell's push to have a trial without the documents and witnesses we've requested,' Schumer wrote.

Pentagon officials expressed concern that Donald Trump's directed military freeze of millions in aid to Ukraine was unlawful

Leaked: The email naming the president was originally released by the Department of Defense redacted but its contents have now been leaked

Senate Minority Leader Chuck Schumer put on a statement regarding the revealed emails, claiming this underscores the fact that there needs to be a long impeachment trial in the Senate where witnesses testify under oath

The associate director of national security programs at OMB Mike Duffey (right), sent an email to Elaine McCusker (left), the acting Pentagon comptroller, telling her the instructions to withhold aid was coming directly from the president. 'Clear direction from POTUS to hold,' Duffey wrote of the freeze

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'The American people deserve a fair trial that gets to the truth, not a rigged process that enables a cover-up,' he continued in the tweet.

The emails reveal that Michael Duffey, associate director of national security programs at the Office of Management and Budget, sent an email on July 25 to top DOD officials directing the Pentagon to suspend future military aid to Ukraine.

'Based on guidance I have received and in light of the Administration's plan to review assistance to Ukraine, including the Ukraine Security Assistance Initiative, please hold off on any additional DOD obligations of these funds, pending direction from that process,' Duffey wrote in the email, which was sent just hours after Trump held his now-infamous phone call with Ukrainian President Volodymyr Zelesnky.

'We intend to formalize the pause with an apportionment footnote to be provided later today,' he continued. 'Given the sensitive nature of the request, I appreciate your keeping that information closely held to those who need to know to execute the direction.'

During his July 25 call, Trump asked Zelesnky to open an investigation into political rival and former Vice President Joe Biden and his son Hunter's business dealings in Ukraine.

The call was the genesis of an anonymous whistle-blower's allegations that led to the Democrats launching an impeachment inquiry into Trump.

Democrats claimed the president was setting a quid pro quo with Ukraine by demanding an investigation while holding up millions in military assistance.

In December the House voting, nearly along party lines, on two articles of impeachment: abuse of power and obstruction of Congress.

The articles, however, haven't been moved to the Senate.

Senate Majority Leader Mitch McConnell is vehemently against impeachment, as are most other Republicans in Congress, and claims he would swifty move the articles through the upper chamber with ultimate acquittal of the president.

McConnell and other Republicans claim they want a speedy trial without any witnesses, insisting the impeachment proceedings are a distraction by Democrats from other issues facing America.

The Kentucky Republican says the Senate would instead rely on the testimony from witnesses who appeared before the House in its impeachment investigation.

The Republican-controlled chamber insisted it would acquit the president in as little time as possible.

House Speaker Nancy Pelosi, who announced the impeachment probe at the end of September, claim there is no time limit for when they have to move articles of impeachment to the Senate.

Trump spent his Christmas holiday in West Palm Beach, where he is still vacationing at his Mar-a-Lago resort, rage tweeting at Pelosi, demanding she present the two articles of impeachment to the Senate.

'Crazy Nancy Pelosi should spend more time in her decaying city and less time on the Impeachment Hoax!' he said, invoking one of his many nick names for the California Democrat.

'Why should Crazy Nancy Pelosi, just because she has a slight majority in the House, be allowed to Impeach the President of the United States? Got ZERO Republican votes, there was no crime, the call with Ukraine was perfect, with ''no pressure,'' he tweeted on Christmas morning.

Schumer, who serves as the Senate minority leader, said revelations of the redacted emails are working against Republicans' strategy to have a swift trial.

Schumer (pictured) specifically said acting Chief of Staff Mick Mulvaney and Duffey should testify. 'This new evidence raises questions that can only be answered by having the key Trump administration officials... testify under oath in a Senate trial'

The New York Democrat says he also feels the emails prove witnesses need to be called in the Senate to further expand on allegations against Trump – he cited specifically Trump's acting chief of staff and Duffey.

'This new evidence also raises questions that can only be answered by having the key Trump administration officials– Mick Mulvaney, John Bolton, Michael Duffey and Robert Blair– testify under oath in a Senate trial,' he wrote in a statement Thursday.

'Importantly, that Mr. Duffey said there was 'clear direction from POTUS to continue to hold' only further implicates President Trump and underscores the need for the Senate to subpoena the witnesses and documents we've requested at the onset of a trial,' he continued.

Duffey, on August 6, sent an email to Elaine McCusker, the acting Pentagon comptroller, telling her he planned to extend the hold on Ukraine military funding.

McCusker wrote back asking who Duffey spoke with about the additional freeze.

A few days later she wrote to senior OMB officials, including Duffey, saying she did not feel the pause could be executed.

'As we discussed, as of 12 AUG I don't think we can agree that the pause 'will not preclude timely execution.' We hope it won't and will do all we can to execute once the policy decision is made, but can no longer make that declarative statement,' McCusker wrote.

Pentagon officials felt Trump's freeze was breaking the Impound Control Act, which requires the executive branch to spend money as Congress appropriated it.

To make sure money wasn't being taken advantage of the White House has to notify Congress if money is being held or shifted elsewhere.

Defense Secretary Mark Esper's chief of staff told McCusker at the end of August that Secretary of State Mike Pompeo would talk with Donald Trump the next day to communicate 'more privately' about the matter.

August 30, following the aforementioned meeting, Duffey emailed McCusker.

'Clear direction from POTUS to continue to hold,' he wrote, adding he would be sending new paperwork over to extend the freeze.

Trump rages against 'dirty (filthy) cops' and claims everyone investigating him would be jailed for 'treason and more' as he enters 2020 claiming he is victim of 'the crime of the century'

After a mostly quiet New Year's Day, President Trump started out the second day of 2020 on a Twitter tear.

'A lot of very good people were taken down by a small group of Dirty (Filthy) Cops, politicians, government officials, and an investigation that was illegally started & that SPIED on my campaign,' Trump began. 'The Witch Hunt is sputtering badly, but still going on (Ukraine Hoax!),' he said, referring to his impeachment that is heading to a Senate trial later this month.

The president said that if the FBI had spied on a Democrat's campaign 'everybody involved would long ago be in jail for treason (and more), and it would be considered the CRIME OF THE CENTURY, far bigger and more sinister than Watergate!' he roared.

President Trump dashed off these two tweets, calling the FBI initially looking into his campaign using FISA warrants the 'CRIME OF THE CENTURY, far bigger and more sinister than Watergate!'

President Trump's motorcade is seen driving through the entryway of his West Palm Beach golf club Thursday morning

The president dashed off the tweets before heading from Mar-a-Lago, where he's spent the holidays among family, friends and political allies.

He then headed to his nearby Trump International Golf Club in West Palm Beach, Florida, where it's sunny and could reach 80 degrees. Protesters against banning vape flavors stood along the motorcade's route again Thursday.

Trump has continued to fixate on the FBI's decision to wiretap his 2016 campaign's foreign policy adviser Carter Page, especially after Department of Justice Inspector General Michael Horowitz found 17 'significant errors or omissions' on the Foreign Intelligence Surveillance Act - or FISA - applications used.

He's tried to suggest that corrupt individuals within the ranks of the DOJ and the FBI were responsible for the convictions of his associates Paul Manafort, Rick Gates, Michael Flynn, George Papadopoulos, Michael Cohen and, more recently, Roger Stone - who will all serve jailtime due to Special Counsel Robert Mueller's Russian interference probe.

And the president continues to tie together the Mueller probe and the reason he was impeached: he's accused of holding up $400 million in military aid to Ukraine to pressure the country's president to announce an investigation into a political rival, Democratic 2020 hopeful Joe Biden.

The cases are linked by a thread - that Trump also hoped that Ukrainian President Volodymyr Zelensky would investigate the origins of the 2016 Russia probe, as the president has latched onto a conspiracy theory that Ukraine - not Russia - interfered in the 2016 presidential election.

Trump was impeached in the House of Representatives on December 18, but the articles of impeachment haven't been delivered to the Senate yet, as they're being held up by House Speaker Nancy Pelosi as lawmakers from the two parties bicker over the rules.

A source confirmed to DailyMail.com the Senate Majority Leader Mitch McConnell and Senate Minority Leader Chuck Schumer hadn't talked impeachment over the holidays. McConnell is expected to make an update Friday.

The Senate returns in full to Washington next week.