Acting defense secretary Christopher Miller said in a statement that the Defense Department “will continue to provide all required support” to the transition team, and that defense officials were working to reschedule “approximately 20 interviews with 40 officials until after January 1.”

Those meetings, initially scheduled for Friday, were postponed after legal officials in the Pentagon raised concern that they could not keep up with the work, said a senior U.S. official, who spoke on the condition of anonymity due to the sensitivity of the issue. The Pentagon did not dispute that Miller’s decision about meetings on Friday were a surprise to the Biden team.

Miller said that the meetings can be held after a “mutually-agreed upon holiday pause,” and that he is “committed to a full and transparent transition” with the Biden team. His “key focus” over the next two weeks, he said, is supporting requests for information about the U.S. military’s involvement in the effort to distribute coronavirus vaccines, and other pandemic information, he said.

“This is what our nation expects and the DoD will deliver AS IT ALWAYS HAS,” Miller said in his statement.

But the Biden team said they are concerned about delays.

Yohannes Abraham, the executive director of the transition, said in a call with reporters that there “was no mutually agreed upon holiday break” and while the Biden team has received “widespread cooperation on transition,” there have been “pockets of recalcitrance, and DOD has been one of them.”

Jennifer Psaki, a spokeswoman for the Biden transition, declined to say that Miller was lying, but said reporters could make their “own judgment about the information we provided.”

“It’s not in our interest to provide inaccurate information,” she said.

Trump administration officials did not offer an explanation for why additional transition meetings in the Pentagon cannot be held before January.

The disagreement comes at a time when the Defense Department, in addition to having a leading role in overseeing vaccine distribution, is assessing what may have been compromised in a hack of government networks that analysts and U.S. officials speaking privately have attributed to Russia, and carrying out a partial withdrawal of several thousand U.S. troops from Afghanistan by Inauguration Day at President Trump’s behest.

The Trump administration also has purged numerous officials from nonpartisan Pentagon advisory boards in recent days, installing Trump loyalists in their place.

The tension also comes after the transition began later than normal, as Trump disputed the election results in numerous states and spread unfounded conspiracy theories of widespread voter fraud.

President-elect Joe Biden was declared the winner on Nov. 7, but the Trump administration declined to certify ascertainment until Nov. 23. The step acknowledges who the apparent winner of an election is, and allows government agencies to begin meeting with transition officials.

Defense officials have held 139 interviews with 265 officials since the transition began, defense officials said Friday.