USA share futures and the dollar tumble in Asian trade on Wednesday after reports President Donald Trump asked then-FBI Director James Comey to end an investigation into Michael Flynn.
The revelation raised the political peril for Mr Trump's White House by introducing the possibility that the president may have obstructed justice, an impeachable offence.
The Washington Post also published a report which alleged that Trump shared "highly classified" information with Russian Foreign Minister Sergei Lavrov and Russian ambassador Sergey Kislyak during a White House meeting last week.
Comey prepared the account immediately after his meeting with the president, and sent copies of the memo to Federal Bureau of Investigation leadership and to some of his closest associates.
The latest Russian twist, first reported by the New York Times, comes a week after Mr Trump fired Mr Comey over his handling of the FBI investigation into Hillary Clinton's use of a private email server while at the state department.
"I hope you can see your way clear to letting this go, to letting Flynn go", the president told Mr Comey, according to the memo.
According to the NY Times, Comey wrote a memo directly after an Oval Office meeting with Trump in which he quoted the President as saying "He is a good guy, I hope you can let this go". The White House on Tuesday defended President Donald Trump's disclosur.
In response to the report, a White House official pointed out that acting FBI director Andrew McCabe had testified last week that there had been "no effort to impede our investigation to date".
Legal experts point to two opinions written by the Department of Justice's Office of Legal Counsel (OLC) in 1973 and 2000, both concluding that indictment or criminal prosecution of a sitting President would impermissibly undermine the capacity of the executive branch to perform its constitutionally assigned functions. I need to see it sooner rather than later.
Utah Congressman Jason Chaffetz says that he has his "subpoena pen ready".
Mr Trump spoke hours after Paul Ryan, the most senior Republican in Congress, warned against "rushing to judgment" on the latest scandal to engulf the president. Trump has been a one-man wrecking ball in the daily news cycles for the past 125 days.
"If his objective was to see that Flynn got a square deal then I think that's entirely appropriate", Franks said. "I don't think he meant to obstruct justice".
Twitter reacts to Spurs getting blown out without Kawhi Leonard
The Spurs were outscored 58-33 after Leonard left as they could not survive without their best offensive and defensive player. You ever hear of manslaughter? It's onto a new series, so I don't see how you can get overconfident playing a new team.
Many lawyers say impeachment is only viable penalty for a president's actions in office.
Rep. Adam Schiff, a Democrat from California and the ranking member of the House Intelligence Committee, also indicated he would utilize all the power at his disposal to obtain the reported memo. "And there's more behind it".
Others expected the transcript from that meeting or a briefing.
He and other Democrats said Mr Comey must testify before lawmakers about his conversations with the president.
Senate Minority Leader Charles Schumer said he was shaken by the report in the NYT. This allowed his opponents to claim that the admission proved he had caused an obstruction of justice-one of the possible grounds for impeachment.
"Three words: Obstruction of justice", Toobin told Wolf Blitzer.
"The memo is powerful evidence of obstruction of justice and certainly merits immediate and prompt investigation by an independent special prosecutor", said Democratic US Senator Richard Blumenthal.
"I don't know the facts, so I really want to wait until I find out what the facts are before commenting", Sen. "But if somebody came and tried to bring pressure on me to stop prosecution back then I'd call it obstruction", Mr Leahy said.
The Republican chairman of the House oversight committee is requesting that the FBI turn over all documents and recordings that detail communications between former FBI Director James Comey and President Donald Trump. "Following shortly on the heels of the President's admission that he raised his own potential liability at a dinner with the Director and at a time when the Director was concerned about keeping his job, the allegations paint an alarming portrait of a President potentially interfering with, or worse, obstructing, the progress of the Russian Federation investigation".
"Let's get to the bottom of what happened with the director. This is not a truthful or accurate portrayal of the conversation between the President and Mr Comey", the official said requesting anonymity.
US officials said Trump discussed intelligence about Islamic State with Russian Foreign Minister Sergei Lavrov and Russian Ambassador Sergei Kislyak at last Wednesday's meeting.