CNN  — 

The Biden transition team has declined to give outgoing acting Defense Secretary Christopher Miller office space and resources for his transition out of the role, according to a Biden transition official.

It is typically a courtesy to provide transitioning office space and resources to departing secretaries of defense, and the decision reflects the extraordinary bitterness of the presidential transition.

“Given Mr. Miller’s acting capacity in that role, as well as reduced staffing and occupation of the Pentagon and auxiliary offices during Covid-19, we deemed it appropriate not to extend that perk in this instance,” the official said. Miller was named acting secretary on November 9.

CNN has asked the Department of Defense for comment. But the decision prompted a parting shot from an outgoing Trump administration official familiar with the transition.

“Excuses aside, the American people see this break in a long tradition of accommodation, proper records management, continuity of government and good manners for what it is: the last petty act of this transition’s intransigent party,” the official said.

Tensions between the Biden transition and Trump’s political appointees at the Pentagon simmered for weeks, coming to a head in late December when the transition team disputed suggestions from Pentagon officials who questioned the accuracy of the President-elect’s assertion that the Department of Defense has refused to brief his team on the massive cyberattack on government agencies and major American technology and accounting companies. Unnamed Pentagon officials essentially accused Biden of lying when he was discussing the attack with reporters and said that the Defense Department “won’t even brief us, on many things.”

Earlier that month, Biden’s transition team said that they had not agreed to a two-week break in critical transfer-of-power discussions with Pentagon officials, despite an assertion from the acting Defense secretary that both sides had agreed to take such a “holiday pause.” The tensions spilled into public view after Miller had said the incoming Biden team had agreed to a two-week holiday break in previously scheduled transition talks at the Pentagon.

The strained relationship between the incoming and outgoing administrations has seen several controversial last minute moves.

The National Security Agency said Sunday it was installing Trump National Security Council staffer Michael Ellis as its general counsel, after Miller ordered NSA Director Gen. Paul Nakasone to place the Trump loyalist into the role. The move is significant because the role of general counsel at the country’s largest intelligence agency is a civil service position, not a political role, meaning it could be difficult for the Biden administration to remove Ellis. The strategy of trying to install political loyalists into career positions is known as “burrowing” in the government.

Miller’s appointment preceded a post-election purge that saw some of the senior-most Defense Department civilians ousted in a matter of days, including the leaders of the Defeat-ISIS task force, the top Pentagon officials overseeing policy and intelligence, and the undersecretary of defense for intelligence, among others. The positions were quickly filled with individuals perceived as Trump loyalists.

Miller has stated that he “cannot wait to leave this job,” according to a transcript released by the Department of Defense. The admission came as the Pentagon said at least 25,000 National Guard were being mobilized in Washington, DC, amid security concerns around this week’s inauguration following the deadly riot at the US Capitol.

CNN’s Oren Liebermann, Jeff Zeleny, Sarah Mucha, Jeremy Herb and Zachary Cohen contributed to this report.