The reports raised questions over whether obstruction of justice charges could be laid against Trump, weakening confidence in the US president's ability to push through an aggressive stimulus program that investors had been banking on since his election in November.
Reports seeped out of the White House that Trump is incandescent with the performance of his staff and is mulling a huge overhaul of the top officials who surround him.
The New York Times says Trump made the request to Comey during a February meeting.
The encounter between Comey and Trump unfolded after the Federal Bureau of Investigation director was in the Oval Office briefing the President along with Vice President Mike Pence and Attorney General Jeff Sessions, according to a source close to Comey who has a copy of the memo.
"I hope you can let this go", Trump told Comey, according to the FBI's former director memo quoted by The New York Times.
February 14, 2017: Comey speaks with Trump in the Oval Office a day after Flynn is ousted.
The Times posted its report under a banner headline, while declaring, in the text of the article, "The existence of Mr. Trump's request is the clearest evidence that the president has tried to directly influence the Justice Department and F.B.I. investigation into links between Mr. Trump's associates and Russian Federation".
Even if this didn't lead to a criminal conviction, such a request could add to the basis for impeachment for obstruction of justice.
That memo was drafted by Mr. Comey in February, noting what he thought were the president's improper actions concerning influencing an ongoing investigation.
Just as President Richard Nixon fired Archibald Cox because he felt the special prosecutor breathing down his neck, President Donald Trump has sacked James Comey because he feared the FBI's Trump-Russia probe was encroaching on his tinpot throne.
The newspaper said Mr Comey was in the Oval Office that day with other national security officials for a terrorism threat briefing.
The Comey memo's emergence had congressional Democrats suggesting that the president engaged in obstruction of justice, an impeachable offense. At their news conference, Ryan and other House Republican leaders talked about National Police Week and their plans to overhaul the USA tax code before reporters raised questions about the Trump controversies. Trump tells The Associated Press by telephone after the meeting that he "learned a lot" but declines to say whether he accepted their conclusion about Russian Federation.
An administration official confirmed to AFP on condition of anonymity that the original intelligence came from Israel.
Two more key domestic promises that Trump has so far dramatically under-delivered on.
Yes, the president said, he had given information to the Russians.
Republican senator Angus King told CNN that the possibility of impeaching Donald Trump is getting closer after it emerged that the president asked former director of the FBI, James Comey, to shut down an investigation into Mike Flynn, Trump's former national security advisor. The crisis atmosphere within the administration was reflected in the fact that State Department officials were unaware of the Tillerson statement when contacted by the press.
Republican senators have also expressed some frustration with questions of credibility now surrounding the White House while simultaneously derailing the GOP agenda and messaging.
Funding for Trump's envisioned border wall with Mexico, meanwhile, was omitted from a budget deal struck last month on Capitol Hill.
The White House denied the account. "I'd like to think somebody from the White House who was in the room is going to get on the phone and tell me what they said". "The chaos that is being created by the lack of discipline is creating an environment that I think makes-it creates a worrisome environment".
Making matters worse, the White House was not returning calls to Republican allies, which was also causing consternation. "The speaker hopes for a full explanation of the facts from the administration".
If it was deemed, meanwhile, that Trump was guilty of one of the "high crimes and misdemeanours" worthy of impeachment, it would have to be supported by a two-thirds majority in the Senate, which would require a significant number of Trump's party to turn against him.
Testifying before Congress is familiar to Comey, a former Justice Department official in the George W. Bush administration.
"The president can claim he was raising an issue of concern for a longtime associate", Turley said.