At first Trump and his staff claimed he moved against Comey based on a Tuesday memo from Deputy Attorney General Rod Rosenstein condemning Comey's handling of the Clinton email probe. The FBI is investigating Russia's meddling in the 2016 election and possible collusion with Trump's campaign and aides.
"The president has nothing further to add on that", White House Press Secretary Sean Spicer said at the daily briefing when asked several times by reporters about the president's tweet Friday morning referring to "tapes" of Comey. During an exclusive interview Thursday with NBC News' Lester Holt, Trump said he'd previously planned to fire the Federal Bureau of Investigation director - which conflicted with what staffers and surrogates previously told the media about Comey's surprise ouster.
"If, in fact, there are such recordings, I think those recordings will be subpoenaed and they will probably have to turn them over", said Lee.
Trump, in his termination letter to Comey, said Comey told him on three different occasions that Trump wasn't under investigation.More news: Ringling's final show commences after 146 years
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When Mason asked why Trump sent the tweet and how it should be interpreted, Spicer responded with his new favorite catchphrase "the president has nothing to add".
Apparently angered by criticism of the different accounts of the sacking, Mr Trump used another of his tweets on Friday to say: "As a very active President with lots of things happening, it is not possible for my surrogates to stand at podium with flawless accuracy!"
Spicer said the tweet was "not a threat" warning Comey not to talk to the press. "Maybe the best thing to do would be to cancel all future "press briefings" and hand out written responses for the sake of accuracy???"
CNN cited an unnamed source as saying Mr Comey was "not anxious about any tapes" Mr Trump may have of their conversations. "I will have group conference calls with multiple witnesses", Watts said.
In 1973, President Richard Nixon sacked Archibald Cox, the Watergate special prosecutor who was seeking access to tapes of presidential conversations that ultimately led to Mr Nixon's resignation.