White House press secretary Sean Spicer repeatedly refused on Friday to deny that Donald Trump is secretly taping visitors.
He tweeted that Mr Comey had "better hope there are no "tapes" of our conversations", suggesting such tapes, if they existed, might contradict him.
Associates said Comey is furious about the lack of respect he was shown during his abrupt firing Tuesday and has been angered by comments by Trump and White House staffers, reported ABC News.
Two top Democrats are demanding that the White House turn over any recordings of conversations between President Donald Trump and former FBI Director James Comey.
But this appeared to undermine earlier comments from administration officials that Mr Comey had been fired on the recommendation of Attorney General Jeff Sessions and his deputy Rod Rosenstein.
"I have long believed that a President can fire an FBI Director for any reason, or for no reason at all", Comey told former colleagues in a letter he delivered.
When the president fired Comey, it made him the first since Nixon to fire a law enforcement official officially investigating something tied to the White House.
There is also a suggestion Mr Comey had asked for more resources for the Federal Bureau of Investigation inquiry.
Sources said Comey rejected a pledge of loyalty during a private dinner with the president and instead opted to offer a pledge of honesty.
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A source close to the former Federal Bureau of Investigation chief told CNN on Friday that Comey is "not anxious about any tapes" as he enjoys his sudden vacation at home in northern Virginia.
Reporters also peppered Spicer with questions about whether Trump was recording in the Oval Office and Spicer responded that he had nothing further to say.
But Spicer insists that, "the tweet speaks for itself". Trump wrote. "Maybe the best thing to do would be to cancel all future "press briefings" and hand out written responses for the sake of accuracy???"
Spicer also pushed back on characterizations about the nature of the tweet saying it was "not a threat".
Nick Ackerman, a former Assistant U.S. Attorney for the Southern District of NY and an assistant Watergate prosecutor, told MSNBC that the situation reminds him of Watergate and makes him wonder if Trump recorded Comey or if the president is trying to intimidate him by implying he has a tape.
Michael Beschloss, a leading presidential historian, said on Twitter: "Presidents are supposed to have stopped routinely taping visitors without their knowledge when Nixon's taping system was revealed in 1973".
CNN cited an unnamed source as saying Mr Comey was "not anxious about any tapes" Mr Trump may have of their conversations.
The potential threat posed by Comey apparently prompted Trump to reveal a tape recording system at the White House that could potentially be subpoenaed by congressional investigators in their ongoing Russian Federation probe.
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