WASHINGTON — Legendary journalist Bob Woodward on Sunday clashed with his former Watergate reporting partner over the intelligence briefing of President-elect Donald Trump on the salacious allegations contained in an unverified dossier of opposition research.

“I’ve lived in this world for 45 years where you get things and people make allegations,” Woodward told “Fox News Sunday.”

“That is a garbage document. It never should have been presented in — as part of an intelligence briefing.”

Woodward also said that “Trump’s point of view” was being “under-reported,” noting that outgoing White House counsel Neil Eggleston could have given the briefing to incoming counsel Don McGahn.

“So Trump’s right to be upset about that,” Woodward said. “And I think if you look at the real chronology and the nature of the battle here, those intelligence chiefs who were the best we’ve had, who were terrific and have done great work, made a mistake here. And when people make mistakes, they should apologize.”

Trump later tweeted his appreciation.

“Thank you to Bob Woodward,” Trump wrote, along with a recap of Woodward’s comments and the word “apologize” in all capital letters. “Media should also apologize,” Trump added.

Ex-Washington Post reporter Carl Bernstein — with whom Woodward shared the Pulitzer Prize for exposing the Watergate scandal that brought down President Richard Nixon — last week helped CNN break the story that Trump and President Obama were both given a two-page summary of the dossier.

The claims — which Trump has denied — were provided as part of a classified presentation on alleged Russian meddling in last year’s election.

Bernstein last week appeared to endorse inclusion of the blockbuster claims in the briefing, after Trump denounced CNN’s reporting as “fake news.”

“The best obtainable version of the truth is that the chief intelligence officials of the United States of America saw this material, thought that it deserved investigation, thought that it ought to be brought to the attention of the president of the United States and to the president-elect,” Bernstein said during a Wednesday panel discussion on CNN’s “AC 360.”

During a Wednesday appearance on SiriusXM radio, Bernstein also said: “It’s not fake news, otherwise seniormost intelligence chiefs would not have done this,” according to a tweet from host Michael Smerconish.

Also on “Fox News Sunday,” outgoing CIA Director John Brennan blasted Trump for alleging that “the intelligence agencies” leaked the dossier and calling it “something that Nazi Germany would have done and did do.”

“I do take great umbrage at that, and there is no basis for Mr. Trump to point fingers at the intelligence community for leaking information that was already available publicly,” Brennan said.

When challenged by host Chris Wallace, who noted that the “rumors” hadn’t previously been reported and suggested a “staff level” briefing would have been more appropriate, Brennan said officials wanted to be “sure that the president-elect himself was aware of it.”

Brennan also said Trump would soon face “numerous” challenges — including terrorism, “the cyber-challenge,” North Korea and the Middle East — and needed to understand “this is more than being about him.”

“And he has to make sure that now he’s going to have the opportunity to do something for national security, as opposed to talking and tweeting, he’s going to have tremendous responsibility to make sure that US national security interests are protected and are advanced,” Brennan said.

Meanwhile, BuzzFeed editor-in-chief Ben Smith doubled down on his decision to publish the entire dossier in the wake of CNN’s report, saying “our job is not to be gatekeepers to decide what to suppress and keep from our audience. It’s primarily to share with our audience what we’ve got.”

“There was a big difference between saying, ‘There are these dark and explosive claims that we’re not going to tell you about’ and ‘Here’s the actual thing,'” Smith told CNN’s “Reliable Sources.”