0625 GMT July 22 2017
The calls for the memo's release intensified after media outlets reported that Trump had asked Comey - whose bureau was investigating the Trump campaign's alleged ties with Russia - to drop an inquiry about former national security adviser Michael Flynn, who was forced out over "improper contacts" with Moscow.
Flynn (pictured below) resigned in February following revelations that he and the Russian ambassador to Washington had discussed US sanctions on Moscow before Trump took office and misled Vice President Mike Pence about the conversations.
Comey, who was fired in a surprise move last week, wrote the memo detailing his conversation with Trump immediately after the meeting, which took place the day after Flynn resigned.
According to the memo, details of which were first revealed by The New York Times, Trump told the then-FBI chief, "I hope you can see your way clear to letting this go, to letting Flynn go."
The news provoked backlash from members of Congress, who renewed calls for Comey to testify on Capitol Hill. The lawmakers also called for an independent investigation into the Trump campaign's possible connections to Russia.
Nancy Pelosi, the top Democrat in the House of Representatives, said in a statement that Trump abused his “executive power” and “obstructed justice.”
"If these reports are true, the president's brazen attempt to shut down the FBI's investigation of Michael Flynn is an assault on the rule of law that is fundamental to our democracy.”
"I don't want to read a memo. I want to hear it from him (Comey)," said Republican Senator Lindsey Graham in an MSNBC interview.
"@GOPoversight is going to get the Comey memo, if it exists. I need to see it sooner rather than later. I have my subpoena pen ready," Republican Representative Jason Chaffetz, chairman of the House Oversight and Government Reform Committee, said in a tweet.
Later on, Chaffetz sent a letter to the FBI, asking for all memos, notes and recordings between Comey and Trump by May 24.
Democratic Senator Richard Blumenthal told CNN that this is "an obstruction of justice case unfolding in real time."
"And I'm still stunned that more of my Republican colleagues are not standing strong and speaking out."
"We're a long ways from a conviction - the fact that we simply have a headline in The New York Times," Republican Representative Trey Gowdy said on Fox News.
The White House denied the version of events in the memo, saying, “While the president has repeatedly expressed his view that General Flynn is a decent man who served and protected our country, the president has never asked Mr. Comey or anyone else to end any investigation, including any investigation involving General Flynn.”
The developments come days after Washington was rocked by reports that Trump shared "highly classified information" with senior Russian diplomats during a recent meeting at the White House.