Sarah Sanders, the White House press secretary, has defended claims she repeatedly made to reporters in 2017 regarding Donald Trump’s firing of then FBI director James Comey – despite admitting to investigators for the special counsel Robert Mueller that they had no basis in fact.

Sanders admitted in statements to the special counsel that her repeated claims that the president fired Comey because the rank-and-file of the FBI had lost confidence in him as FBI director were “a slip of the tongue” and “not founded on anything”, according to the redacted version of the Mueller report released on Thursday.

The long-awaited report – the product of a two-year investigation into Russian interference in the 2016 US election and the Trump campaign – exposed a culture of lying at the White House.

The report included multiple examples of Trump’s current and former press secretaries making false claims to journalists, particularly in the days after Comey’s firing.

Sanders told the special counsel’s office that a statement she made to journalists about how the White House had heard from “countless members” of the FBI that Comey lacked support within the agency, “was not founded on anything”.

Yet on Friday, Sanders appeared on ABC’s Good Morning America and appeared to stand by the statement she had admitted was a lie.

Asked by TV host George Stephanopoulos about her “deliberate false statement” she said: “They [FBI rank-and-file] continued to speak out and said that James Comey was a disgrace, a leaker. I stand by the fact, George.”

Stephanopoulos, a former White House communications director under Bill Clinton, interrupted, saying: “[You admitted] those comments weren’t founded on anything, when you faced criminal penalty.”

On @GMA, White House press sec. Sarah Sanders sought to double down on past statements she made that special counsel Robert Mueller's team said were "not founded on anything."



Watch the full interview: https://t.co/7mRpysmjN1 pic.twitter.com/wrHqaXgyp7 — ABC News (@ABC) April 19, 2019

Sanders answered: “It was the heat of the moment, meaning that it wasn’t a scripted talking point. I’m sorry that I wasn’t a robot like the Democratic party.”

Sanders’ claim on 10 May 2017, the day after Comey was fired, that “countless members of the FBI” opposed Comey was “a slip of the tongue”, Sanders told the special counsel’s office in an interview last year.

Sanders repeated that “slip of the tongue” during a press briefing the following day, when skeptical White House reporters questioned her on her claim that Comey did not have support within the FBI’s rank-and-file. One reporter asked what basis the White House had for that conclusion, given that the FBI’s acting director had publicly said that Comey still had the support among the FBI’s agents.

“I can speak to my own personal experience,” Sanders told the White House press. “I’ve heard from countless members of the FBI that are grateful and thankful for the president’s decision.” She went on: “I’ve certainly heard from a large number of individuals. And that’s just myself. And I don’t know that many people in the FBI.”

“You personally have talked to countless officials, employees, since this happened?” another reporter asked later.

“Correct,” Sanders said.

“I mean, really?” the second reporter asked.

“Between, like, email, text messages – absolutely,” Sanders said.

“Fifty? Sixty? Seventy?” the reporter asked.

“Look, we’re not going to get into a numbers game. I have heard from a large number of individuals that work at the FBI that said they’re very happy with the president’s decision. I don’t know what else I can say.”

A year later, in interviews with the special counsel’s office, Sanders said “that her statement in a separate press interview that rank-and-file FBI agents had lost confidence in Comey was a comment she made ‘in the heat of the moment’ that was not founded on anything”.

Sean Spicer, the White House press secretary at the time, also made a false claim to reporters about Comey’s firing, telling journalists the night Comey was fired that the decision to fire him “was all” Rod Rosenstein, the deputy attorney general.

Rosenstein said in an interview with the special counsel’s office that he had told other justice department officials that night that he would not participate in putting out a “false story” that Comey’s firing had been his idea.

Sanders replaced Spicer as White House press secretary in July 2017.

The White House’s public press briefings to journalists have become increasingly rare and increasingly brief, another issue of concern for the American press and White House transparency.