Comey had been leading the FBI investigation into whether the Trump campaign colluded with Russian officials until Trump fired him last week. Republican Congressman Justin Amash also said Wednesday that if the New York Times' account is true, it constitutes grounds for impeachment.
Neil Eggleston, former President Barack Obama's White House counsel during the last years of his administration, responded similarly. The latest accusation claims that President Trump illegally shared classified information with Russian Foreign Minister Sergey Lavrov.
What does Michael Flynn's resignation mean for Trump?
The White House has played down the importance and secrecy of the information Trump gave to the Russians, which had been supplied by Israel under an intelligence-sharing agreement.
Trump says, "we want to bring this country of ours together".
Republicans and Democrats alike were eager to hear from Comey, who has increasingly emerged as a central figure in the unfolding drama.
The statement also said the panel had asked Andrew McCabe, the acting FBI director, to send any notes or other memos prepared by Comey about communications he may have had with senior White House and Department of Justice officials in relation to the investigation into Russian Federation and the 2016 election.
Democratic Senator Richard Blumenthal also told reporters that Mueller was conducting a criminal investigation, including into whether there was any obstruction of justice on behalf of Trump's campaign team.
Mukasey and Eggleston were asked to address a range of subjects related to the executive branch and its place in the separation of powers - as well as Trump's unique status as one of the weakest chief executives in history.More news: ICJ ordered Pakistan not to execute Kulbushan Jadhav
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"Zero", Trump said, adding, "My total priority, believe me, is the United States of America". Trump traveled to CT earlier in the day to give the commencement address at the U.S. Coast Guard Academy. I guess that's why we won. "And the more righteous your fight, the most opposition you will face".
Earlier Wednesday, the Justice Department announced it has appointed former FBI Director Robert Mueller as special counsel to investigate Russia's involvement in the US presidential election. "I hope you can see your way clear to letting this go, to letting Flynn go", Trump told Comey, according to the memo as reported by the Times.
"I think it's reaching the point where it [Trump controversies] is of Watergate size and scale", McCain said.
Republican Speaker of the House Paul Ryan however said it was crucial to let investigations run their course before rushing to judgment. The contents of the memo have subsequently been confirmed by other news organizations, including Bloomberg, although the memo itself has not yet surfaced publicly.
He reportedly shared the memo with top Federal Bureau of Investigation associates. "They [citizens] deserve an FBI Director that is above reproach".
The Times report comes after a week of bombshell stories surrounding the Trump administration.
Mark Warner of Virginia, top Democrat on the Senate intelligence committee, said he would ask Comey for additional material as part of that panel's investigation.