Newly revealed emails show that the Office of Management and Budget repeatedly ignored warnings from the Pentagon that President Donald Trump's decision to freeze a nearly $400 million military-aid package to Ukraine was illegal.

The emails were released to the Center for Public Integrity following a Freedom of Information Act lawsuit, but the Justice Department redacted significant portions.

On Thursday, the national-security blog Just Security published unredacted versions of the emails that revealed the lengths to which the Justice Department went to conceal the Defense Department's concerns about the Ukraine aid freeze.

Here's a timeline of what happened in the days leading up to Trump's decision to lift the hold after the public learned of his actions.

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For weeks, officials at the Office of Management and Budget ignored warnings from the Department of Defense that placing a hold on a congressionally appropriated $391 million military-aid package to Ukraine violated the law, according to new unredacted emails obtained by Just Security and published Thursday.

The emails between Defense Department and OMB officials were secured through a lawsuit under the Freedom of Information Act launched by the Center for Public Integrity. In December, a court ordered the federal government to turn over 300 pages of emails, many of which were heavily redacted.

The unredacted emails published by Just Security revealed that between June and September — when the aid was ultimately released following an anonymous whistleblower's complaint — the Defense Department repeatedly asked the OMB why the military aid was being held up.

Crucially, the department warned several times that continuing to withhold the aid violated the Impoundment Control Act, which stipulates that if the federal funds are not spent on their designated purpose within a certain period, they will be taken, or impounded, by the Treasury Department.

In this case, the aid had to be released by September 30.

Here's a timeline of what happened in the crucial days leading up to the aid's release:

As The New York Times recently reported, an OMB aide, Robert Blair, learned on June 19 that Trump was questioning the delivery of the aid package, at which point Blair told Russell Vought, the acting head of the office, that "we need to hold it up."

that Trump was questioning the delivery of the aid package, at which point Blair told Russell Vought, the acting head of the office, that "we need to hold it up." That day, another OMB official, Michael Duffey, emailed the acting Defense Department comptroller, Elaine McCusker, and copied Mark Sandy, an OMB official on national-security programs, to ask if she had "insight on this funding," according to the emails published by Just Security.

After McCusker explained on June 25 which companies were producing the military equipment and said that only $7 million of the Pentagon's $250 million part of the package had been spent, Blair told Mick Mulvaney, the acting White House chief of staff, on June 27 that they should "expect Congress to become unhinged" by withholding the aid.

which companies were producing the military equipment and said that only $7 million of the Pentagon's $250 million part of the package had been spent, Blair told Mick Mulvaney, the acting White House chief of staff, on that they should "expect Congress to become unhinged" by withholding the aid. On July 25 , Sandy officially froze the Ukraine aid. This was also the day Trump spoke with Ukrainian President Volodymyr Zelensky on the phone and asked him to investigate former Vice President Joe Biden and his son Hunter.

, Sandy officially froze the Ukraine aid. This was also the day Trump spoke with Ukrainian President Volodymyr Zelensky on the phone and asked him to investigate former Vice President Joe Biden and his son Hunter. Shortly after Trump's call, Duffey emailed several Pentagon officials and asked them to "please hold off on any additional DOD obligations of these funds." He requested that the recipients keep the directive "closely held to those who need to know" because of "the sensitive nature of the request."

McCusker replied that day and asked whether the OMB had cleared the hold with the Defense Department's lawyers. This was the first sign of the Pentagon's concerns about the legality of withholding the aid. The Justice Department redacted McCusker's question.

On July 26 , John Rood, the head of policy at the Pentagon, emailed Defense Secretary Mark Esper a readout of a meeting in which top national-security officials voiced their "unanimous support" for sending the security assistance.

, John Rood, the head of policy at the Pentagon, emailed Defense Secretary Mark Esper a readout of a meeting in which top national-security officials voiced their "unanimous support" for sending the security assistance. On August 9 , McCusker warned Sandy, Duffey, and other senior OMB officials that if the aid was not released soon, it might affect the "timely execution" of the program. "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," she wrote. The DOJ redacted this warning from McCusker, which, notably, contradicted the OMB's talking points.

, McCusker warned Sandy, Duffey, and other senior OMB officials that if the aid was not released soon, it might affect the "timely execution" of the program. "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," she wrote. On August 12 , when it became clear that Trump would continue the aid freeze, McCusker emailed Duffey and asked him to include language in a footnote in a budgeting document to reflect the growing risk of withholding funding. The language was not included, and the request was redacted in the initial document release.

, when it became clear that Trump would continue the aid freeze, McCusker emailed Duffey and asked him to include language in a footnote in a budgeting document to reflect the growing risk of withholding funding. The language was not included, and the request was redacted in the initial document release. The DOJ also redacted several emails from McCusker near the end of August raising additional legal questions about withholding the aid and the possibility that Trump's actions violated the Impoundment Control Act.

raising additional legal questions about withholding the aid and the possibility that Trump's actions violated the Impoundment Control Act. In one noteworthy exchange on August 27 that was redacted, McCusker said the situation surrounding the aid freeze was "particularly difficult because OMB lawyers continue to consistently mischaracterize the process."

that was redacted, McCusker said the situation surrounding the aid freeze was "particularly difficult because OMB lawyers continue to consistently mischaracterize the process." Another redacted portion contained information about a draft letter from the defense secretary to a senior OMB official highlighting the divisions between the two agencies over the legality of freezing Ukraine's military aid.

On August 28 , after Politico publicly revealed the aid freeze, the OMB's general counsel, Mark Paoletta, sent around talking points including that "no action has been taken by OMB that would preclude the obligation of these funds before the end of the fiscal year." McCusker pushed back, writing: "I don't agree to the revised TPs — the last one is just not accurate from a financial execution standpoint, something we have been consistently conveying for a few weeks." Her response was initially redacted.

, after Politico publicly revealed the aid freeze, the OMB's general counsel, Mark Paoletta, sent around talking points including that "no action has been taken by OMB that would preclude the obligation of these funds before the end of the fiscal year." As September came around, McCusker raised concerns about whether the Defense Department would be "adequately protected from what may happen as a result of the Ukraine obligation pause." She added, "I realize we need to continue to give the WH has much decision space as possible, but am concerned we have not officially documented the fact that we can not promise full execution at this point in the [fiscal year]."

On September 9 , Duffey sent McCusker a misleading email suggesting that if the president greenlighted the aid but the Pentagon was not able to obligate the funding, it would be on the Pentagon and not the OMB. McCusker responded: "You can't be serious. I am speechless."

, Duffey sent McCusker a misleading email suggesting that if the president greenlighted the aid but the Pentagon was not able to obligate the funding, it would be on the Pentagon and not the OMB. On September 11 , after Congress became aware of a whistleblower's complaint accusing Trump of "using the power of his office to solicit interference from a foreign country" in the 2020 election, Duffey emailed McCusker and said the president had lifted the hold on Ukraine's military aid. "Glad to have this behind us," he wrote.

, after Congress became aware of a whistleblower's complaint accusing Trump of "using the power of his office to solicit interference from a foreign country" in the 2020 election, Duffey emailed McCusker and said the president had lifted the hold on Ukraine's military aid.

In response to Just Security's reporting, an OMB official denied that there were tensions between the Pentagon and the office. "There was agreement every step of the way between DOD and OMB lawyers, who were responsible for working out the details of the hold, in line with the President's priorities," the official told CNN.

Trump's decision to withhold the aid, as well as other actions he and his allies took to pressure Ukraine to cave to his personal political demands, formed the basis of a congressional impeachment inquiry that began in September. On December 18, the House of Representatives impeached Trump on charges of abuse of power and obstruction of Congress.