On Friday, a person close to the former director recounted a Comey-Trump dinner in January at which Trump asked for a pledge of loyalty, The Associated Press reported.
"No", Spicer said unequivocally.
President Trump said he hopes to "make a fast decision" on the replacement for fired FBI Director James Comey, hinting an announcement could come within days. Mr Comey's associates said the new President requested the dinner he described.
White House spokeswoman Sarah Huckabee Sanders said that President Trump had considered firing the FBI Director since he came to office, NBC reports.
The White House said Mr Comey was sacked over the FBI's mishandling of the investigation into Hillary Clinton's email practices.
In a Tweet, Trump wrote that "James Comey better hope that there are no "tapes" of our conversations before he starts leaking to the press!"
Meanwhile, Trump's threat of releasing "taped" conversations between himself and Comey is conjuring up further comparisons to former President Richard Nixon, the paranoid former president who taped his conversations. Later, the president and his advisers said Mr Trump had planned to fire Mr Comey since taking office. "That would be flawless".
The controversy began this morning, when Trump again took aim at the investigation into his administration and its potential ties to Russian Federation, while blasting the "fake media" and its coverage of the issue.
The mere sight, though, of the president appearing to warn - or, as some might see it, threaten - the former Federal Bureau of Investigation director on the public forum of Twitter is surely a first.
Rod Rosenstein, the deputy U.S. Attorney General, will brief all 100 senators next week in a closed session that Sen.
Allies and former employees of Mr. Trump have long said that he taped some of his own phone calls, as well as meetings in Trump Tower. The president also threatened to cancel the century-old policy of daily White House press briefings if criticism of their accuracy continues.
Trump's administration has offered countless different accounts about the timeline of Comey's firing. "[Rosenstein] made a recommendation, but regardless of recommendation, I was going to fire Comey".