Three of Donald Trump's former employees say they witnessed him recording phone calls at Trump Tower inNew York before he became president.

The ex-employees told the Wall Street Journal that Trump had one or more recording devices that he would sometimes use to tape conversations with associates.

They claim to have seen the devices being used to record conversations when they worked for Trump as high-level employees over a period spanning 30 years.

A fourth person, who was an associate of Trump's, told the outlet he knew the then-businessman had recorded one of their conversations because it was later used as evidence in a lawsuit.

Three of Donald Trump's former employees say they witnessed him recording phone calls at Trump Tower in New York before he became President

Recording conversations is not illegal in New York as long as at least one person involved is aware it is being taped.

The four associates and employees said they were not surprised that Trump mentioned recording conversations this week.

It comes after Trump lobbed a veiled threat at former FBI director James Comey on Friday, hinting that some of their conversations before his firing may have been taped.

'James Comey better hope that there are no "tapes" of our conversations before he starts leaking to the press!' the president tweeted.

It's unclear whether Trump was warning that the White House is recording his calls, or if he believes the FBI may have been recording Comey's.

The White House have not yet commented on the issue.

White House press secretary Sean Spicer told reporters Friday afternoon that the Oval Office would be silent on the matter: 'The president has nothing further to add on that.'

Challenged about the tweet itself, Spicer said: 'That's not a threat. He's simply stating a fact.'

The stunning move adds a new level of intrigue to the firing of the nation's former top cop

Donald Trump warned former FBI director James Comey (pictured) that their conversations may have been preserved on 'tape'

White House press secretary Sean Spicer said Friday afternoon that the Oval Office wouldn't have any further comments about the tweet, which he denied was a 'threat' to Comey

But Comey, according to CNN, which cited an unnamed source, is 'not worried about any tapes' of conversations between him and the president. 'If there is a tape, there's nothing he is worried about.'

And NBC News had its own secret access to Comey's inner circle, with one person close to him saying: 'He hopes there are tapes. That would be perfect.'

Trump said Thursday during an interview with NBC News that the two men have spoken at least three times since Inauguration Day.

And on those occasions, he insisted, Comey assured him that he was not personally the subject of any federal investigations.

'He said it once at dinner and then he said it twice during phone calls,' Trump said.

He described a matter-of-fact exchange over dinner in which he asked an unusual question and got an unconventional response.

'I said, "If it's possible would you let me know, am I under investigation?" Trump recalled.

'He said, "You are not under investigation".'

Spicer was asked Friday whether or not the White House had a recording of that dinnertime conversation, and replied: 'I'm not aware of that.'

Trump said Thursday that Comey told him – three times – that he wasn't being investigated

It is rare for a federal law enforcement official to tell anyone, including the President of the United States, whether they are being investigated.

The latest twist from Trump amid reports that he demanded loyalty from James Comey during the private dinner at the White House back in January.

The claims come from associates of the now fired FBI director. Comey had told associates that he was summoned to the White House for a one-on-one dinner with Trump seven days after the inauguration, the New York Times reports.

It was during the dinner that Trump reportedly asked Comey twice to pledge loyalty to him as the new Commander in Chief.

Sources claim Comey declined to do so but said he told the President he would always be honest with him.

Trump is said to have pressed Comey on whether that would be 'honest loyalty', to which the FBI director said: 'You will have that.' Sources close to Comey said he now believes this dinner conversation may have sealed his fate.

This version of events is vastly different to the dinner conversation Trump himself described in an interview with NBC's Lester Holt on Thursday.

The version is denied by the White House. But the president also used Twitter on Friday morning to say that 'it is not possible for my surrogates to stand at podium with perfect accuracy'.

While it is not clear if they are talking about the same dinner, the pair are believed to have only dined together privately once.

Trump indicated that he had dinner with Comey at the former FBI director's request - and said Comey was angling to keep his job.

'I had a dinner with him. He wanted to have dinner because he wanted to stay on. We had a very nice dinner at the White House,' Trump said.

'He asked for the dinner?' Holt followed up.

'A dinner was arranged, I think he asked for the dinner,' the president hedged. 'And he wanted to stay on as the FBI head.

'And I said I'll consider and we'll see what happens. But we had a very nice dinner. And at that time he told me "you are not under investigation",' Trump said.

During that same interview, Trump declared he had planned to fire Comey all along, regardless of whether top Justice Department officials recommended the stunning step.

The White House had initially cited a Justice Department memo criticizing Comey's handling of last year's investigation into Hillary Clinton's emails as the impetus for Trump's decision.

Press Secretary Sean Spicer, Counselor Kellyanne Conway (pictured), Deputy Press Secretary Sarah Huckabee Sanders and Vice President Mike Pence had all claimed that Trump did the firing after he was advised to let Comey go by the deputy attorney general

With Spicer (left) away on Navy Reserve duty, Huckabee Sanders (right) was put behind the White House podium to handle the billowing crisis that prompted comparisons to Richard Nixon's Saturday Night Massacre

Been here before... White House tape threat sounds like Nixon President Nixon resigned before he could be impeached for the Watergate scandal President Donald Trump said in a Twitter tirade Friday morning that sacked FBI director James Comey 'better hope that there are no "tapes" of our conversations before he starts leaking to the press.' Presidential recordings of course have played a part in history before - notoriously so in the case of Richard Nixon. He resigned before he could be impeached after the infamous Nixon White House tapes that were made public before the Senate Watergate Committee. Nixon ordered the Secret Service to install recording devices in the White House and taped 2,636 hours of phone calls and conversations between 1971 and 1973. He was paranoid about how he was viewed by members of Congress and the executive branch. The 37th president was also concerned about how he was being portrayed to the media. Most people did not know they were being taped and only a few members of the White House administration knew the sound activated recording devices existed. Nixon's downfall spiraled because of the tapes which were exposed during the Watergate investigation into the DNC burglary while he was running for re-election. President Nixon ordered the firing of special prosecutor Archibald Cox (pictured) who was investigating the break-in at the DNC headquarters at the Watergate complex The burglars were trying to bug the DNC headquarters at the Watergate complex. During the investigation, the 'smoking-gun' tape led to Nixon's resignation. It proved the president ordered a cover-up of the burglary of the DNC. The recording revealed Nixon ordering the FBI and CIA to abandon its investigation of the break-in. Before the release of the 'smoking gun' tape, Nixon ordered the firing of special prosecutor Archibald Cox - who was investigating the Watergate scandal - in the Saturday Night Massacre, which itself has drawn comparisons to the firing of Comey. Nixon was pardoned by his successor, Gerald Ford, but many of his aides served time in federal prison. Nixon wasn't the first president to secretly record Oval Office conversations. President Franklin Delano Roosevelt also recorded discussions in the Oval Office with a microphone hidden under his desk. President Franklin Delano Roosevelt used a recording device hidden under his desk after a New York Times article containing 'a deliberate lie' was publsihed He began using the device after the New York Times published what he claimed to be a fictitious article. FDR was advised by his stenographer to record meetings to keep this from happening again. He recorded eight hours of conversations in the Oval and stopped using it after he was re-elected in 1944. President Dwight D. Eisenhower also used a secret recording device disguised as a telephone on his desk in the Oval Office. FDR could only tape 10 minutes at a time with his recorder, but Eisenhower was able to record a full 15 minutes. However, Eisenhower would occasionally forget to turn the machine on at the beginning of meetings and the quality of many recordings was extremely poor. He used the device to document 75 different conversations beginning in 1953. President Eisenhower (pictured with Vice President Nixon) used a recording device hidden in a fake telephone . However, he often forgot to turn it on before meetings President John F. Kennedy had a system installed in 1962 by the White House Communications Agency. He hid microphones in the drapes of the Cabinet Room and under a coffee table and his desk in the Oval. Kennedy had a Dictaphone machine hooked up to a telephone and taped 265 hours of meetings and 12 hours of phone calls. His Vice President Lyndon B. Johnson also used a device and as president he used it to record 800 hours covering 9,000 phone conversations. JFK upped the number of devices in the White House from previous administrations. Recorders were hidden in the drapes of the Cabinet Room, his study and in the Oval President Johnson used secret recording devices as vice president and president Again, the quality of the Dictaphone recordings were often lacking. The tapes would often pick up background noise and JFK's leg tapping more than the actual conversation. President Ronald Reagan also taped dozens of calls made from the Situation Room. The recordings reveal the conversations he had with world leaders such as former Israeli Prime Minister Menachem Begin, former Syrian President Hafez el-Assad and former British Prime Minister Margaret Thatcher. Ronald Reagan taped dozens of calls made from the Situation Room, including one with former British Prime Minister Margaret Thatcher (left) Source: History.com, Richard Nixon Presidential Library and Museum, The Institute: The IEEE News Source and CNN Advertisement

But Trump acknowledged for the first time on Thursday that the Russia investigation - which he dismissed as a 'made-up story' - was also on his mind as he ousted the man overseeing the probe.

The shifting accounts of the decision to fire Comey, whom Trump derided as a 'showboat' and 'grandstander,' added to a mounting sense of uncertainty and chaos in the West Wing, as aides scrambled to get their stories straight and appease an angry president.

Not even Vice President Mike Pence was spared the embarrassment of having told a version of events that was later discredited by Trump.

Multiple officials, including Pence, said the president was acting at the behest of Rosenstein and Attorney General Jeff Sessions.

'I was going to fire Comey,' Trump said. 'Regardless of recommendation I was going to fire Comey.'

The White House's explanations continued to crumble throughout the day Thursday. On Capitol Hill, acting FBI Director Andrew McCabe strongly disputed the White House's assertion that Comey had been fired in part because he had lost the confidence of the FBI's rank-and-file.

My decision: Trump said of the firing of the FBI director: 'Oh, I was going to fire Comey regardless of recommendation.'

White House spokeswoman Sarah Huckabee Sanders insisted she had heard from 'countless' members of the FBI who welcomed the president's decision.

'That is not accurate,' McCabe said. 'Director Comey enjoyed broad support within the FBI and still does to this day.'

McCabe also pointed out the remarkable nature of Trump's version of his conversations with Comey. McCabe told a Senate panel it was not 'standard practice' to tell an individual whether they are or are not under investigation.

Previous presidents have made a public show of staying out of legal matters, so as not to appear to be injecting politics. Trump's comments demonstrated his striking deviation from that practice.

Trump and Comey's relationship was strained early on, in part because of the president's explosive and unsubstantiated claims that Barack Obama 'wiretapped' him.