She added that Rosenstein declined to provide details about Comey's dismissal because she said Rosenstein is anxious to give wide latitude to former FBI Director Robert Mueller, who Rosenstein appointed as special counsel Wednesday to investigate Russian interference in the 2016 USA election.
On Wednesday, Deputy Attorney General Rod Rosenstein appointed former FBI Director Robert Mueller to be the special counsel.
President Donald Trump told news anchors in an off-the-record meeting that the appointment of a special counsel in the Russian Federation probe is bad for the US.
Congress was examining Iran-Contra at the same time that an appointed independent counsel, Lawrence Walsh, was investigating White House aides, including Col. Oliver North, in the arms-for-hostages deal.
"Director Comey was very unpopular with most people", Trump said Thursday at a White House news conference.
"The shock to the body is that this is now a criminal investigation", Graham (R-SC) told reporters moments after he exited the Senate chamber.
Vermont's two U.S. Senators praised the appointment of a special prosecutor to oversee the FBI investigation into potential collusion between associates of President Donald Trump and the Russian government. Trump fired Comey the next day.
Despite initially opposing appointment of an independent counsel, Republican House Speaker Paul Ryan said Thursday that the development "helps assure people and the Justice Department that they're going to go do their jobs independently and thoroughly, which is what we've called for all along".
In particular, Mr Trump referenced Mr Comey's "poor performance" at a Senate committee hearing the previous week, noting that the Federal Bureau of Investigation had been forced to adjust the record.More news: Steelers release Ladarius Green, Greg Warren
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Rosenstein's decision to appoint Mueller as special counsel could impede the congressional probes, senators said.
This has added potency to allegations that Mr Trump, who has struggled to shake off suspicions that Russian Federation helped put him in the White House, was seeking to block the investigation by sacking FBI chief James Comey. It is my hope and expectation that the former FBI Director will run a thorough investigation that uncovers all the facts.
Speaking to the press at the White House after a meeting with Colombian President Juan Manuel Santos, Trump categorically rejected accusations that he pressured the FBI into closing the investigation into his former National Security Adviser Michael Flynn.
In a statement, Rosenstein said he had chose to hand off the high-profile inquiry to a figure outside the normal government chain of command, including the White House, "in order for the American people to have full confidence in the outcome".
On Wednesday, Mr Trump was quoted in a White House statement as saying: "I look forward to this matter concluding quickly".
In March, Rosenstein made no pledge to Leahy and other Democrats to appoint a special counsel.
"I would be very discouraged if somehow this new special prosecutor would preclude Jim Comey from testifying in public before our committee", he said.
During an interview with NBC News last week, Trump said, "Oh, I was going to fire regardless of recommendation".
Rosenstein was originally invited by the two Senate leaders, Republican Mitch McConnell of Kentucky and Democrat Chuck Schumer of NY, to explain Trump's firing of FBI Director James Comey. But a spokesman for the senator later said that Flynn still has time to comply if he chooses to.