The Trump administration has refused to allow members of President-elect Joe Biden’s transition team to meet with officials at U.S. intelligence agencies that are controlled by the Pentagon, undermining prospects for a smooth transfer of power, current and former U.S. officials said.

The officials said the Biden team has not been able to engage with leaders at the National Security Agency, the Defense Intelligence Agency and other military-run spy services with classified budgets and global espionage platforms.

The Defense Department rejected or did not approve requests from the Biden team this week, the officials said, despite a General Services Administration decision Nov. 23 clearing the way for federal agencies to meet with representatives of the incoming administration.

The delays came even as Biden advisers spent much of this week meeting with officials at the Office of the Director of National Intelligence and the CIA, intelligence agencies that are independent of the Defense Department.

But Pentagon officials said their agency was taking steps required to provide outside officials access.

Sue Gough, a Defense Department spokeswoman, said Friday that the Biden team “has not been denied any access.” After being asked by The Washington Post about the apparent standoff, Gough said the requested meetings could take place as early as next week.

By then, Biden advisers will have waited more than a month since the election to have meaningful contact with intelligence agencies that have multibillion-dollar budgets, satellite networks that ring the planet and vast surveillance authorities.

The delays have added to the unprecedented tensions surrounding the transition, fueled by a president who refuses to concede that he lost the election and spent much of his tenure accusing the nation’s spy agencies of disloyalty to him.

A Biden transition team spokesman declined to comment, as did NSA and DIA officials.

Current and former officials, who spoke on the condition of anonymity to discuss a sensitive matter, said the delays have impaired the Biden team’s ability to get up to speed on espionage operations against Russia, China, Iran and other U.S. adversaries.

The inability to meet with the NSA was described as particularly worrisome. The agency is the largest U.S. intelligence service, and its eavesdropping capabilities have been a critical source of intelligence on threats as varied as weapons proliferation and foreign interference in U.S. elections.

Officials said that rejections relayed this week to the Biden team cited seemingly petty procedural barriers.

One person said the Pentagon had asked repeatedly for rosters of those who would take part in a visit, lists of topics and estimates of time to be allotted — information that in some cases had been provided at the outset.

“If they were in a cooperative mood, none of this would be happening,” said another person with knowledge of the interactions.

The Pentagon has been in significant turmoil since the election. Acting secretary of defense Christopher C. Miller was installed last month after Trump fired Mark T. Esper, his Pentagon chief.

Miller has presided over the removal of senior Pentagon officials, replacing them with perceived Trump loyalists including chief of staff Kash Patel and Ezra Cohen-Watnick, who is serving as interim undersecretary of defense for intelligence. In her statement to The Post, Gough indicated that Cohen-Watnick’s office has played a central role in matters related to the transition.

Pentagon officials in turn blamed Biden advisers. One defense official, who spoke on the condition of anonymity, citing the sensitivity of the subject, said that Biden transition officials had improperly contacted agencies directly to arrange visits and briefings, and were told that they instead needed to submit requests to the Pentagon.

The result has been an awkward standoff in which former officials were spurned by agencies they formerly helped run. Among those ex-officials is Vincent Stewart, a retired three-star U.S. Marine Corps general who previously served as DIA director and is a leading member of the Biden intelligence transition team.

Other spy agencies have been far more receptive. At the CIA, for example, the Biden transition team has had extensive access to senior officials, computer equipment connected to the agency’s classified systems, and office space at “Scattergood,” a historic homestead on the CIA compound often used for hosting VIPs.

Biden recently named Avril D. Haines, a former top White House official and deputy director of the CIA, as his nominee to be director of national intelligence. Biden has made no other announcements about his intelligence team, but former deputy CIA director David S. Cohen is seen as a top candidate to be the director of that agency.

While scrutiny intensifies of the transition at Defense Department intelligence agencies, officials have taken steps to advance that effort at the Pentagon itself. The first virtual meeting between the Pentagon’s internal transition task force and the Biden team occurred Nov. 25. Since then, officials have taken administrative actions including granting access badges for the Biden team and completing non-disclosure agreements, Pentagon officials said.