Rudy Giuliani came out swinging Thursday following a report – later retracted – that federal investigators had tapped phones belonging to President Donald Trump's former personal lawyer Michael Cohen.

NBC News reported that the wiretaps were in place during the weeks before agents raided Cohen's home, offices and hotel room on April 9.

But the network later walked its story back, broadcasting an update on MSNBC that read: 'Correction: Feds are monitoring, not listening to Cohen's calls.'

Giuliani, the former New York City mayor who is the president's newest legal spokesman, was furious that the news was leaked at all, and had said Attorney General Jeff Sessions should intervene and put the people behind the Cohen probe 'under investigation.'

'I am waiting for the attorney general to step in, in his role as defender of justice, and put these people under investigation,' Giuliani told The Hill, a Washington, D.C. newspaper.

He predicted the president would be outraged by the prospect of the FBI listening to private conversations with the man who was recently his attorney, and conceded that he would have to tell Trump that 'the Department of Justice seems to want to trample all over the Constitution of the United States.'

Ultimately, Giuliani said in a separate interview, he doesn't believe there was a wiretap – even though prosecutors in New York have already said in court filings that they had also obtained warrants to sift through Cohen's email accounts.

Giuliani was technically right.

Rudy Giuliani accused Special Counsel Robert Mueller's office of leaking information about a federal wiretap warrant on Michael Cohen's phones, but correctly claimed the 'tap' wasn't real – and then called on Attorney General Jeff Sessions to intervene anyway and investigate the investigators

NBC News reported that Michael Cohen, President Donald Trump's former longtime personal attorney, was the subject of a wiretap warrant before the April 9 raid on his room at the Loews Hotel (shown), his home and his offices; the network later changed its story

Following a frenzied day-long news cycle, NBC News corrected its reporting to reflect that the federal government was keeping a record of calls to and from Cohen's phones, but not actually snooping on who was speaking or what was being said

Cohen's home in New York City's Trump Park Avenue building was swept up in the federal raid, following what was thought to be weeks of phone surveillance

'Us lawyers have talked about it, we don’t believe it’s true,' he told The Daily Beast, referring to the wiretap story.

Cohen has offices at 30 Rockefeller Center; that space was raided along with his home and hotel room

'We think it’s going to turn out to be untrue because it would be totally illegal. You can’t wiretap a lawyer, you certainly can’t wiretap his client who’s not involved in the investigation.'

'No one has suggested that Trump was involved in that investigation. So they’re going to wiretap the lawyer, his client, and his client the president of the United States? I don’t think so, not if they want to stay out of jail. [And] disclosing a wiretap is a federal felony.'

NBC News reporter Tom Winter, who broke the corrected story, appeared on MSNBC to clarify that investigators were keeping track of calls made to and from Cohen's phones – but not hearing what was said.

'We reported that there was a wiretap on Michael Cohen's phone, meaning that they were able to listen in to conversations,' Winter explained.

'Now three senior U.S. officials are telling us that ... it was not a wiretap. Instead it was what is referred to as a "pen register." In plain English that means it's a log of phone calls that were made from a specific phone line or specific phone lines.'

Winter cautioned that the weaker form of surveillance on a personal lawyer affiliated with the President of the United States 'doesn't change the legal bar, here, to get a warrant of this type. It's still a very serious matter.'

Giuliani had earlier blasted Special Counsel Robert Mueller's office for what he said was an inappropriate and illegal leak about what should have been a sealed court order.

'Look at all of the bad faith we’re seeing here. And whether this wiretap story is true or not true, it’s bad faith to leak it,' he said.

'We should find out about this with a notification from the Justice Department, they’re wiretapping the President of the United States, they’re wiretapping a man talking to his lawyer and then they want us to cooperate? We’re not suckers.'

What started as a report of a wiretap later became a milder story about a 'pen register' that tracks metadata about calling numbers, the length of calls and when they occurred

Cohen was photographed Thursday walking to a Manhattanhotel where he maintains a room

Michael Avenatti, the combative attorney representing pornographic actress Stormy Daniels, said on MSNBC that was likely the FBI raided Cohen quickly because federal agents heard him in a phone call discussion the destruction of evidence. NBC news later retracted its report, saying there was no live surveillance of Cohen's calls

It's still not clear who provided NBC News with the information about a live wiretap, which the network corrected hours later.

The news from NBC briefly injected a new degree of gravity into Cohen's legal jeopardy, and opened wider the range of materials the FBI might have at the ready to connect the president to an infamous $130,000 hush-money payment to a porn star who claims she slept with a then-married Trump.

NBC had reported that the feds intercepted at least one phone call between a Cohen-linked phone number and the White House. With the network's correction later in the day, that appeared implausible.

Such a call could have connected Cohen to anyone at 1600 Pennsylvania Avenue.

According to NBC, the president had called Cohen once after the FBI raid but then cut off all communications with him – because Giuliani warned him that the bureau could be snooping.

Michael Avenatti, the lawyer for the porn star who claims she slept with President Trump, initially thought the wiretap story was accurate – and left this tweet up after NBC pulled its reporting back

The National Enquirer is a supermarket tabloid run by longtime Trump friend David Pecker; its recent attack on Cohen may have been a warning shot to intimidate him out of 'flipping' on the president as the special counsel circles overhead

Cohen has acknowledged making a $130,000 payment during the waning weeks of the 2016 presidential campaign to Stephanie Clifford, who acts in pornographic movies under the stage name Stormy Daniels.

Daniels had claimed she had a sexual affair with Donald Trump a decade earlier, when future first lady Melania Trump had recently given birth to their son Barron.

Cohen's payment was part of a nondisclosure agreement that Daniels has since flouted, claiming it's invalid because Trump himself never signed it.

Ethics watchdogs have speculated that Cohen could be indicted for violating campaign finance law if there's proof the money changed hands as part of a strategy to save the president's election hopes.

Giuliani said Wednesday night that Cohen paid the money out of his own pocket in order to save Trump from personal embarrassment and divorce, and revealed that Trump had later reimbursed the funds as part of a months-long legal retainer.

Stormy Daniels' attorney @MichaelAvenatti reacts to Cohen wiretap.



"I think ultimately it will be disclosed that during these wiretaps the FBI learned of means by which Michael Cohen was going to destroy ... evidence or documentation." pic.twitter.com/55vrt30jcQ — MSNBC (@MSNBC) May 3, 2018

Daniels' combative lawyer Michael Avenatti said Thursday that federal investigators' tentacles were likely longer than they appeared.

'If the NBC reporting re: audio wiretaps is true, and I have every reason to believe it is, the pucker factor associated with Mr. Cohen and the President will remain immeasurable for the weeks and months to come,' he tweeted – leaving that message up even after NBC pulled back its reporting.

Avenatti had said hours earlier that agents surveilling Cohen likely feared he would destroy evidence – prompting them to execute their no-knock warrant last month.

That, he suggested, could explain why they raided Cohen's home, hotel and office instead of merely subpoenaing his files, emails and phone data.

'Here’s what I think ultimately we’re going to find out,' he said on MSNBC. 'I don't think we're going to find out that this was confined just to emails or voice wiretaps. I think they also – my understanding is that they were also wiretapping text-message communications for the weeks leading up to the FBI raids,'

Avenatti spoke just minutes after incorrect news of an audio wiretaps broke.

Giuliani is blaming Special Counsel Robert Mueller's office for the leak that led to Thursday's feeding frenzy about a possible wiretap capturing Cohen's phone calls for weeks before the FBI raided him

Adult-film star Stormy Daniels' lawsuit against Cohen is an attempt to be released from a nondisclosure agreement she signed just before the 2016 election, forbidding her from discussing her claims of a Trump affair in exchange for a $130,000 payment that's now the center of a quickly expanding legal controversy

'I also think that ultimately it will be disclosed that during these wiretaps the FBI learned of means by which Michael Cohen and others were going to potentially destroy or spoliate evidence or documentation,' he said.

'Once they had that information in hand, that is what served as the predicate, or the basis for them to be able to go in and get the warrants to search the home, the office and the hotel room of Michael Cohen.'

Avenatti also opined: 'I do not think this is going to bode well for the future of Michael Cohen or for Mr. Trump.'

'And I think that the amount of evidence that was obtained by the use of those three search warrants, as well as warrants on the electronic communications and the telephone, ultimately are going to be very fruitful for criminal investigators and also likely for us.'

'This is not going to end well,' he concluded.

The question of whether or not Cohen will 'flip' on his longtime former boss and legal client is Washington's favorite parlor game, but it's unclear what kind of information he might have that's not protected by attorney-client privilege.

The president's campaign organization has paid more than $200,000 to cover Cohen's legal expenses. The funds went to a law firm representing Cohen in his legal battles.