Washington: James Comey, the former FBI director, will testify publicly about his role in the investigation into Russian meddling in the election and any possible connections to the campaign of President Donald Trump, the Senate Intelligence Committee announced on Friday.

Comey’s handling of the investigation, including his several conversations with Trump since his election, has taken on added importance since his dismissal and subsequent reports that the president had asked Comey to shut down part of the inquiry, and then later called him a “nut job” in meetings with Russian officials.

“I am hopeful that he will clarify for the American people recent events that have been broadly reported in the media,” said senator Richard M. Burr, the Republican from North Carolina and chairman of the committee. Senator Mark Warner, the Democrat from Virginia, said he expected Comey to “shed light on issues critical to this committee’s investigation of Russian interference in the 2016 election.”

The announcement that Comey would testify followed closely the disclosure by the Justice Department that Rod J. Rosenstein, the deputy attorney general, had spoken with attorney general Jeff Sessions about replacing Comey last winter, before either man had been confirmed for his position in the Trump administration.

Rosenstein revealed that detail in two briefings to members of Congress this week, according to remarks released on Friday by the Justice Department. His testimony provides fuller details about Trump’s termination of the top law enforcement official investigating whether his campaign colluded with the Russian government to influence the outcome of the 2016 election.

During his meetings with lawmakers, Rosenstein said that his conversations with Sessions revealed his long-held belief that Comey should be replaced based on his public statements related to the investigation of Hillary Clinton, beginning in July 2016.

“Among the concerns that I recall were to restore the credibility of the FBI, respect the established authority of the Department of Justice, limit public statements and eliminate leaks,” he said, echoing the sentiments he had outlined in a May 9 memo that the White House released publicly that day and cited as the basis for the firing.

But on May 8 — the day before Rosenstein drafted that three-page memo, he told lawmakers — he had learned of Trump’s intention to remove Comey from the job.

“I thought it was appropriate to seek a new leader,” he said, expressing more direct support for the firing than he had in his more measured memo, which stopped short of endorsing a particular action but rather outlined what he called Comey’s “serious mistakes” and noted that any possible decision to dismiss Comey “should not be taken lightly”.

Trump acknowledged, in an interview with NBC News, that he had decided to fire Comey before reading the memo by Rosenstein.

The release of the testimony followed what was otherwise an unremarkable appearance before House members on Friday, the day after he briefed senators, that left many lawmakers frustrated by Rosenstein’s refusal to answer questions about the investigation into Russian meddling in the election.

“What we did not get a clear understanding of was whether the memo was written with or without the urging of the White House,” said G.K. Butterfield, the Democrat from North Carolina.

Seth Moulton, the Democrat from Massachusetts, said there was “considerable frustration” among lawmakers Friday as Rosenstein declined to answer more detailed questions about the events leading to the abrupt termination.

“This renewed my confidence that we should not have confidence in this administration,” Moulton said. Asked whether that included Rosenstein, he said, “I don’t think he did a lot to bolster our confidence in him.”

According to lawmakers and Rosenstein’s prepared remarks, the deputy attorney general offered little clarity about how related congressional inquiries may proceed in light of Rosenstein’s appointment on Wednesday of a special counsel, Robert S. Mueller, to examine the possibility of collusion between Trump’s associates and Russian officials.

The fact that Mueller’s inquiry is focused on possible crimes is almost certain to limit the cooperation of potential subjects of the investigation who might otherwise testify before Congress or share documents.

“Congress is going to want to look over the shoulder of this investigation,” said Darrell Issa, the Republican from California, who was an aggressive chairman of the House oversight committee during the Obama administration. “The executive branch will always try to limit that for fear it will contaminate potential criminal investigations, or leaks.”

“I don’t expect this to be any different,” he added.

Rosenstein instead delivered careful characterisations about the inquiry and deferred to Mueller’s autonomy as special counsel, and a pending investigation into Comey’s conduct by the Justice Department’s inspector general. He said that his memo had not been a legal brief, or a finding of official misconduct by Comey or “a statement of reasons to justify a for-cause termination.”

Jackie Speier of California, a Democrat on the House Intelligence Committee, said on Friday that Rosenstein had made it clear that Mueller would have “carte blanche authority,” but he also reassured lawmakers that he understood the role of Congress.

“I think he’s very respectful of the role that the Congress is playing in doing its investigation,” she said, “and the separate and distinct role that the Department of Justice is pursuing”.

One point where the investigations may meet is with Comey himself, who has been invited to testify by several congressional committees about whether Trump attempted to interfere in the FBI investigation. The Senate Intelligence Committee hearing will be scheduled after Memorial Day.

Representative Elijah E. Cummings of Maryland, the House oversight committee’s top Democrat, said they would have “no problem” sitting down with Mueller to ensure the committee does not interfere in his investigation. They have a responsibility to secure the democratic process from foreign interference, he said.

“The Congress’ role really is to look forward to make sure this does not ever happen again,” Cummings said.