President Donald Trump allegedly asked ousted FBI Director James Comey to "let go" of the investigation into former national security advisor Michael Flynn, NBC News confirmed with multiple sources with first-hand knowledge of a memo written by Comey.

"I hope you can see your way clear to letting this go, to letting Flynn go," Trump told Comey, according to a memo the former FBI director penned soon after the meeting.

The New York Times first reported the existence of the memo. The Washington Post reported, citing people familiar with the matter, that the document is two pages long and highly detailed.

CNN, The Associated Press and Reuters also confirmed the report.

In a statement provided to NBC News, a senior White House official pushed back against the reports.

"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 president has the utmost respect for our law enforcement agencies, and all investigations. This is not a truthful or accurate portrayal of the conversation between the president and Mr. Comey," the official said in a statement.

The Times and NBC News have not seen Comey's actual notes. An associate of Comey's read parts of the document to a Times reporter, the newspaper said.

According to Comey's account of events, the conversation happened the day after Flynn resigned. In February, Flynn left his post after it was discovered he misled Vice President Mike Pence about the nature of his conversations with the Russian ambassador.

A current official told NBC News that Comey and Trump had their conversation after a previously scheduled counter-terrorism briefing in the Oval Office. The person said Jeff Sessions, Jared Kushner, Steve Bannon and Reince Priebus also attended that briefing.

The conversation described in Comey's notes happened after Trump asked Comey to stay following the briefing's conclusion, the official said.

A former federal law enforcement official told NBC that Comey wrote a memo about nearly every interaction with the president.

The Times reported that Comey shared this memo with senior FBI officials, who interpreted Trump's comments as an attempt to affect the course of the investigation. Those people kept details of the conversation between the president and Comey secret, so that it would not influence the ongoing probe, The Times reported.

A former law enforcement official told NBC that even though Comey was disturbed by Trump's suggestion, the FBI director did not feel compelled to resign. The official, a close friend of Comey's, said the director thought he could manage the situation and operate independently. This person told NBC that Comey made sure rank and file FBI agents did not become aware of Trump's request, so that they would not feel chillded.

This revelation comes a week after the president fired Comey and a day after reports that Trump divulged highly classified information with Russian officials.

— NBC News contributed reporting.