WASHINGTON — At some point Wednesday, a sober team of analysts will gather their black satchels and secure communications gear and begin making their way toward Donald Trump’s campaign headquarters to give the president-elect his first unfiltered look at the nation’s intelligence secrets.

The initial presentation is likely to be a read-through of the President’s Daily Brief, the same, highly classified summary of security developments delivered every day to President Barack Obama. After that, U.S. spy officials will schedule a series of meetings to apprise Trump of covert CIA operations against terror groups, the intercepted communications of world leaders, and satellite photos of nuclear installations in North Korea.

The sessions are designed to bring a new president up to speed on the nation’s most precious secrets. But with Trump, the meetings will likely serve as cautious and tense introductory encounters between wary intelligence professionals and a newly minted president-elect who has demonstrated abundant disdain for their work.

A palpable sense of dread settled on the intelligence community on Wednesday as Hillary Clinton, the candidate many expected to win, conceded the race to a GOP upstart who has dismissed U.S. spy agencies’ views on Russia and Syria, and even threatened to order the CIA to resume the use of interrogation methods condemned as torture.

“It’s fear of the unknown,” said a senior U.S. national security official. “We don’t know what he’s really like under all the talk. . . . How will that play out over the next four years or even the next few months? I don’t know if there is going to be a tidal wave of departures of people who were going to stay around to help Hillary’s team, but are now going to be, ‘I’m out of here.’ ”

“I’m half-dreading, half holding my breath going to work today,” said the official, who, like others, spoke on the condition of anonymity, citing the sensitivity of the subject.

Michael Hayden, the former CIA director who in 2008 briefed a highly skeptical President-elect Obama on the agency’s counterterrorism operations, said that intelligence officials are likely to approach their initial meetings with Trump with significant consternation.

“I cannot remember another president-elect who has been so dismissive of intelligence received during a campaign or so suspicious of the quality and honesty of the intelligence he was about to receive,” Hayden said in a telephone interview Wednesday morning. The initial meetings with Trump in the coming weeks are likely to be professionally conducted, he said, but characterized by “a little caution, a little concern.”

Trump has already received at least two preliminary briefings, arranged during the campaign by Director of National Intelligence James R. Clapper Jr. But those were done out of tradition and courtesy, providing both candidates broad overviews of security issues while holding back secrets about drone strikes, eavesdropping capabilities and other covert operations.

Intelligence officials were deeply troubled early in the campaign when Trump declared that he might be inclined to instruct the CIA to resume operations to capture terrorism suspects and subject them to brutal interrogation measures, including waterboarding. That agency program was dismantled in 2009, and measures passed since then would make its resumption illegal.

Trump subsequently backed away from those comments, which were interpreted by some as empty saber-rattling.

“He could revive a program of secret prisons” overseas, said John Rizzo, former longtime general counsel of the CIA, but would likely find it difficult to get any foreign country to agree to host one.

His other problem would be convincing the workforce at the CIA to carry out his wishes. “There would be such pushback,” said Rizzo, whose confirmation as general counsel was derailed because of his participation in crafting the so-called enhanced interrogation techniques used on al-Qaida suspects in the early 2000s. “Given what it cost the agency” in terms of reputation, “there would be extremely strong resistance.”

More recently, U.S. intelligence officials have been disturbed by Trump’s positions on Russia – his statements encouraging Moscow to seek to steal Clinton’s emails and his refusal to believe the intelligence community’s conclusion that the Kremlin was behind a cyberespionage campaign targeting Clinton and the Democratic Party.

That finding was presented to Trump in one of his early intelligence briefings, and then reinforced last month when Clapper’s office took the rare step of issuing a public statement declaring Russia complicit in the hacks.

Trump treated that determination as unfounded rumor. “I don’t know if they’re behind it and I think it’s public relations, frankly,” Trump said last month.

The absence of seasoned national security officials on Trump’s campaign staff has also been a source of concern at the CIA, the Pentagon and other agencies. His most prominent adviser with intelligence-related credentials is retired U.S. Army Lieutenant General Michael Flynn, who was forced out of his job as director of the Defense Intelligence Agency and dined with Russian President Vladimir Putin last year.

Speculation on where Flynn and former New York mayor Rudolph W. Giuliani might serve in a Trump administration added to the unease among national security officials on Wednesday. “Is Giuliani going to be our attorney general?” one official asked.

Some officials drew comparisons to earlier eras, including the administration of President Richard Nixon, that were characterized by White House hostility toward key departments and agencies – noting that the Justice Department, Pentagon and CIA survived.

What Trump has said about the CIA and the military has “put us in a difficult position, but the flip side is there is an institutional ability to survive,” said a second senior U.S. official. “Bureaucracies chug along and take lumps and have conflicts. If you ask about rank and file, for a long time there has been a sense that [presidents and administrations] come and go, but we’re still here. You’ve got to assume that the Foreign Service at State, generals at the Department of Defense, have that belief. There’s an institutional stability built into the system that can withstand spasms.”

The Washington Post’s Dana Priest contributed to this report.