President Trump accused NBC News and its top anchor, Lester Holt, of “fudging” elements of their interview last year in which Trump said he fired James B. Comey over his performance as FBI director, including his handling of an investigation into Russian interference in the 2016 election.

Trump, who made the allegation on Twitter, didn’t specify what he believed was improperly altered in NBC’s broadcast of the interview. He also provided no evidence for his claim.

In his tweet on Thursday, Trump suggested that NBC News Chairman Andrew Lack — whom he referred to as “Andy Lack(y)” — was “about to be fired(?) for incompetence, and much worse.”

He added, “When Lester Holt got caught fudging my tape on Russia, they were hurt badly!”

It was the first time Trump has suggested any impropriety over his interview with Holt in the 15 months since it aired.

In the May 2017 interview, Trump characterized his firing of Comey this way: “In fact, when I decided to just do it, I said to myself, I said, ‘You know, this Russia thing with Trump and Russia is a made-up story. It’s an excuse by the Democrats for having lost an election that they should have won.’ ”

The comment suggested that Trump fired Comey in part because of his leadership of the FBI’s investigation, which involves allegations that Trump’s campaign cooperated with Russian operatives to sway the election.

Trump’s comment has raised questions about whether he sought to undercut and obstruct the investigation by removing the man in charge of it. Special counsel Robert S. Mueller III is investigating whether Trump took actions as president to interfere with an investigation that could implicate him or his top advisers.

Trump also said in the NBC interview last year that he recognized that firing Comey could “confuse people” about his motivations and could “lengthen out [Mueller’s] investigation,” which was just getting started at the time.

Trump’s defenders have argued recently that his comments to Holt last year are widely misunderstood and have been distorted in media accounts.

Former New York mayor Rudolph W. Giuliani, who is acting as Trump’s personal attorney, told Fox News host Sean Hannity last month that Trump “made it clear to Lester Holt that he [fired Comey] knowing that the [Russia] investigation would continue, so he couldn’t obstruct it.” He later said in the same interview that reporters ignore this. “They conveniently leave that off whenever they play that tape,” Giuliani said. “Amazing what they do with tapes.”

Giuliani, however, hasn’t claimed that Holt’s interview, as presented by NBC last year, was manipulated.

In response to Trump’s tweet on Thursday, Democratic Rep. Ted Lieu (Calif.) tweeted: “As a former prosecutor, I know that when defendants make incriminating admissions on tape, they often argue the tape was fudged. They invariably lose because people trust their eyes & ears.”

Representatives of NBC News did not immediately respond to a request for comment.