WASHINGTON — President Trump on Friday warned James B. Comey, the former F.B.I. director he fired this week, against leaking anything negative about the president and put the news media on notice that he may cancel future White House briefings.
In a series of early-morning posts on Twitter, Mr. Trump even seemed to suggest that there may be secret tapes of his conversations with Mr. Comey that could be used to counter the former F.B.I. director if necessary. It was not immediately clear whether he meant that literally, or simply hoped to intimidate Mr. Comey into silence.
“James Comey better hope that there are no ‘tapes’ of our conversations before he starts leaking to the press!” Mr. Trump wrote on Twitter.
Mr. Trump appeared agitated over news reports on Friday that focused on contradictory accounts of his decision to fire Mr. Comey at the same time the F.B.I. is investigating ties between Mr. Trump’s associates and Russia.
The New York Times reported that, in a dinner shortly after his inauguration, Mr. Trump asked Mr. Comey to pledge loyalty to him, which the F.B.I. director refused to do. The story cited two people who heard Mr. Comey describe the dinner, but the White House rebutted the account.
The president also expressed pique at attention on the shifting versions of how he came to decide to fire Mr. Comey. In his first extended comments on the firing on Thursday, Mr. Trump contradicted statements made by his White House spokeswoman as well as comments made to reporters by Vice President Mike Pence and even the letter the president himself signed and sent to Mr. Comey informing him of his dismissal.
The original White House version of the firing was that the president acted on the recommendation of the attorney general and deputy attorney general because of Mr. Comey’s handling of last year’s investigation into Hillary Clinton’s email. But in an interview with NBC News on Thursday, Mr. Trump said he had already decided to fire Mr. Comey and would have done so regardless of any recommendation. And he indicated that he was thinking about the Russia investigation when he made the decision.
Mr. Trump said on Friday morning that no one should expect his White House to give completely accurate information.
“As a very active President with lots of things happening, it is not possible for my surrogates to stand at podium with perfect accuracy!” he wrote on Twitter.
“Maybe,” he added a few moments later, “the best thing to do would be to cancel all future ‘press briefings’ and hand out written responses for the sake of accuracy???”
The threat may have been just a rhetorical point, but Mr. Trump by his own description likes to be unpredictable and does not feel obligated to follow longstanding White House conventions simply because that is the way things have been done for years. Every president in modern times has been frustrated with the news media at points, but they all preserved the tradition of the daily briefing, if for no other reason than to get their message out. Mr. Trump, with Twitter as his own trumpet, may feel less need for that.
There is already precedent for shutting down news briefings during Mr. Trump’s presidency. The State Department for decades held daily briefings with only rare and brief interruptions in a process that was important not only to inform reporters of administration policy, but foreign governments and even the department’s own far-flung diplomats. But such briefings have largely ended during the Trump administration.
Mr. Trump has long been said by allies and former employees to have taped some of his own phone calls, as well as meetings in his Trump Tower offices. During the campaign, Mr. Trump’s aides working on the fifth floor of Trump Tower told reporters they feared their offices were bugged by the candidate’s security team, and they were careful about what they said.
But the implicit threat to Mr. Comey was ripped from a familiar playbook that Mr. Trump relied on during the campaign to silence critics or dissent. During the Republican primaries, he read aloud the mobile telephone number of one rival, Senator Lindsey Graham of South Carolina, from the stage at a rally and encouraged people to flood his phone with calls.
At another point, he threatened on Twitter to tell stories about Joe Scarborough and Mika Brzezinski, the co-hosts of the MSNBC show “Morning Joe,” after they criticized him. He also railed against the wealthy Ricketts family as it was funding anti-Trump efforts, threatening to air some unspecified dirty laundry. And while competing with Senator Ted Cruz of Texas for the Republican presidential nomination, he threatened to expose something unflattering about his opponent’s wife. “Be careful, Lyin’ Ted, or I will spill the beans on your wife!” he said.
In this case, however, the Twitter comment comes in the context of an F.B.I. investigation, and some experts said the president was skirting a legal line. Samuel W. Buell, a Duke University law professor and former federal prosecutor who led the Enron task force, said that although it was ambiguous whether firing Mr. Comey in the first place amounted to obstruction of justice, Mr. Trump’s threats on Twitter to quiet Mr. Comey could more clearly fall into that category.
“Obstruction of an obstruction investigation is also obstruction,” Mr. Buell said. “If this were an actual criminal investigation — in other words, if there were a prosecutor and a defense lawyer in the picture — this would draw a severe phone call to counsel warning that the defendant is at serious risk of indictment if he continues to speak to witnesses. Thus, this is also definitive evidence that Trump is not listening to counsel and perhaps not even talking to counsel. Unprecedented in the modern presidency.”
This is not the first time an administration has challenged Mr. Comey’s version of a prominent conversation. During President George W. Bush’s administration, White House officials disputed Mr. Comey’s account of a hospital room standoff in which Mr. Bush’s top aides tried to pressure John D. Ashcroft, the ailing attorney general, to reauthorize a controversial surveillance program.
Mr. Comey, then the deputy attorney general, was eventually vindicated because the F.B.I. director at the time, Robert S. Mueller III, kept his notes from the encounter — a reminder that note-taking is steeped in the F.B.I. culture.
Mr. Trump’s mention of tapes did nothing to dispel the echoes of Watergate heard in Washington this week. His dismissal of Mr. Comey in the midst of an investigation into Mr. Trump’s associates struck many as similar to President Richard M. Nixon’s decision in October 1973 to fire Archibald Cox, the Watergate special prosecutor, in an episode that came to be known as the Saturday Night Massacre.
In that case, Nixon was mad at Mr. Cox for seeking access to secret White House tapes of the president’s conversations. The Supreme Court eventually forced Nixon to turn over the tapes, which contained evidence pointing to his involvement in the cover-up of the Watergate burglary and led to his resignation in August 1974.
The difference, according to Luke A. Nichter, a historian at Texas A&M University who has specialized in the Nixon tapes, is that “Nixon’s rantings were done in private, on his tapes,” and he did not cancel press briefings.
“The reason I have a hard time with the label Nixonian is that we’ve surpassed it,” Mr. Nichter said. “To be Trumpian is something of a greater magnitude than simply being Nixonian.”
Mr. Trump’s defenders have said that Watergate comparisons are overwrought and that there is no evidence of collusion between Mr. Trump’s campaign and Russia during last year’s election. American intelligence agencies have concluded that Russia tried to meddle in the campaign with the aim of tilting the election to Mr. Trump.
The president has said that any suspicions of collusion are “fake news” and that the Russia investigation is the product of Democrats who are sore losers looking to explain away an election defeat and undermine his legitimacy.
“Again, the story that there was collusion between the Russians & Trump campaign was fabricated by Dems as an excuse for losing the election,” he wrote on Twitter on Friday morning.
He added later that James R. Clapper Jr., the former director of national intelligence, has testified that he knew of no collusion. Mr. Clapper left office on Jan. 20 with the end of President Barack Obama’s administration and has not been involved in the investigation since then.
“When James Clapper himself, and virtually everyone else with knowledge of the witch hunt, says there is no collusion, when does it end?” Mr. Trump asked.
Lawmakers have given conflicting and vague assessments of the evidence so far. A couple of Democrats on the House Intelligence Committee, Representatives Adam B. Schiff and Eric Swalwell of California, have said there is at least some evidence of collusion, but when Senator Dianne Feinstein of California, a Democrat on the Senate Intelligence Committee, was asked last week if there was, she said, “Not at this time.”