Lawyer Michael Cohen also visited the White House to discuss the possibility of hiring personal attorneys for Trump, CNN reported.
Only three United States presidents have ever faced impeachment or imminent threats of impeachment.
Nonetheless, White House lawyers have consulted impeachment experts and begun researching the precise legal proceeding involved in impeachment, according to CNN's sources.
Rep. Ted Lieu (D-Calif.) said Saturday that "it is clear as day" that President Trump attempted to impede the FBI's investigation into alleged ties between his campaign and Russian Federation, calling Trump's actions "a federal crime staring all of us in the face".
These developments come in the wake of the Justice Department's appointment of special counsel Robert Mueller who was the former Federal Bureau of Investigation director to investigate into the alleged Russian meddling in the 2016 election.More news: Sweden drops rape investigation into WikiLeaks head Julian Assange
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U.S. President Donald Trump (L) and first lady Melania Trump (R) walk on the South Lawn prior to their departure on the Marine One from the White House May 19, 2017 in Washington, DC. Even Democrats have tried to calm impeachment talk out of concern it is premature.
A black Texas congressman said Saturday that he's been threatened with lynching by callers infuriated over him seeking impeachment of President Donald Trump.
However, Fox News politics reporter Brooke Singman subsequently tweeted that a White House official claimed to her that the CNN story was "FALSE".
Green on Wednesday took to the House floor to say he believes Trump committed obstruction of justice and no one's above the law.