But he said Tuesday he anticipated the conflict of interest and effectively recused himself on his first day on the job, and was never briefed on the Russian Federation investigation.
Within the last few hours, Trump has confirmed that he is indeed under investigation for obstruction of justice.
Mueller is said to be interviewing as early as this week three top intelligence officials as part of the probe, the Post reported, citing "five people briefed on the requests".
The Senate committee has already begun taking testimony in both closed and open sessions from the nation's intelligence chiefs.
WASHINGTON, D.C.: US Attorney General Jeff Sessions on Tuesday vehemently denied any collusion with Russian Federation to tilt last year's election in Donald Trump's favor, branding the suggestion an "appalling and detestable lie".
Corallo didn't elaborate on why he singled out the Federal Bureau of Investigation as the source of information. Washington Post reporter Adam Entous and his colleagues broke the story last night.
Trump has repeatedly denied colluding with Russian Federation during the presidential campaign, and Comey and others have testified that there is no evidence to the contrary. I understand the adage that often the best defense is a good offense, but none of this is relevant to the basic question: Did President Trump engage in obstruction of justice?
Mr. Sessions' testimony came in the wake of fired FBI Director Mr. Comey's assertion that he believed he was sacked by Mr. Trump as part of an effort to influence the agencies' investigation into Russia's meddling in the presidential polls. Flynn was forced to resign for misleading administration officials about his contacts with Russia's US ambassador.
"He must keep an arms length distance from Jim Comey", Malcolm said but added he personally isn't concerned about Mueller's handling of the investigation.
Justice Department policy is that a sitting president can not be indicted by a grand jury, the Post also reported Wednesday.
Accusations of obstruction arose last month when Trump fired FBI Director James Comey. Instead, experts say the onus would be on Congress to review any findings of criminal misconduct and then decide whether to initiate impeachment proceedings.
They say senior intelligence officials will be interviewed about whether Mr Trump tried to end an inquiry into his sacked national security adviser.
The Post report only further embroils Trump and his presidency in legal problems that also feature lawsuits from the District of Columbia and Maryland, as well as almost 200 congressional Democrats, over his business holdings and foreign governments.
Comey testified that initial explanations that he was sacked because of poor leadership were "lies, plain and simple".
He disputed that his involvement in Comey's firing violated the recusal.
Americans are mixed on whether the Justice Department investigation, now led by Robert Mueller, can be fair and impartial.
Rosenstein deflected by saying that it's possible the memo - and therefore the Comey firing - is part of Mueller's investigation and shouldn't be discussed openly.
Ahead of the hearing there had been suggestions that Sessions might have had a third, unreported, encounter with Kislyak in April 2016, at Washington's Mayflower Hotel, where candidate Trump was giving his first major foreign policy speech.