Trump asked Comey to end investigation of Michael Flynn

US President Donald Trump asked then-FBI Director James Comey to end the agency's investigation into ties between former White House national security adviser Michael Flynn and Russia, according to a source who has seen a memo written by Comey.

“I hope you can let this go,” Trump told Comey, according to a source familiar with the contents of the memo.

Comey wrote the memo after he met in the Oval Office with Trump, the day after the president fired Flynn on 14 February for misleading Vice President Mike Pence about the extent of his conversations last year with Russia's ambassador, Sergei Kislyak.

Trump condemned a series of government leaks to the news media and said the FBI director should consider prosecuting reporters for publishing classified information

The explosive new development on Tuesday followed a week of tumult at the White House after Trump fired Comey and then discussed sensitive national security information about the Islamic State (IS) group with Russian Foreign Minister Sergei Lavrov.

The Comey memo, first reported by the New York Times, is likely to raise questions about whether Trump tried to interfere with a federal investigation.

While the New York Times and other outlets have not seen the unclassified memo, sources close to Comey read portions of it to reporters.

Republican Congressman Jason Chaffetz, who chairs the House Oversight Committee, said he is ready to subpoena the memo.

Chaffetz also sent a letter to the FBI asking for all documents related to Comey and Trump's discussions by 24 May.

“The events of recent weeks also raise questions about whether President Trump breached his oath of office,” Chaffetz said in the letter.

“We have a solemn obligation under the Constitution to act as a check on the Executive Branch and to hold President Trump accountable. It is time to do our job.”

Throwing reporters in jail

The New York Times said that during the Oval Office meeting, Trump condemned a series of government leaks to the news media and said the FBI director should consider prosecuting reporters for publishing classified information.

The White House denied the report in a statement, saying it was "not a truthful or accurate portrayal of the conversation between the President and Mr. Comey".

“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 statement said.

Flynn's resignation came hours after it was reported that the Justice Department had warned the White House weeks earlier that Flynn could be vulnerable to blackmail for contacts with Kislyak before Trump took office on 20 January.

Kislyak was with Lavrov at the White House last week when Trump disclosed the sensitive information.

The new development came as Republican and Democratic lawmakers pressured Trump to give a fuller explanation for why he revealed sensitive intelligence information to Lavrov.

The information had been supplied by a US ally in the fight against IS, the officials said.

US lawmakers react

Democratic lawmakers have reacted fiercely, with some even calling for Trump's impeachment.

“History is watching,” Senate minority leader Chuck Schumer warned in a tweet.

Senator Angus King, an independent who caucuses with the Democrats, said that Congress should begin impeachment proceedings on Trump. "I say it with sadness and reluctance," King said.

Dick Durbin, a Democratic senator, said the memo "appears to cross the line into the obstruction of justice".

And Richard Blumenthal, a Democrat from Connecticut, said in a statement: "We are witnessing an obstruction of justice case unfolding in real time."

"I am stunned that any of my colleagues would possibly oppose the appointment of an independent special prosecutor after this astonishing revelation and other mounting evidence of political interference in a criminal investigation," he said.

All 33 Democrats on the House Oversight and Judiciary committees sent a letter to chairman Jason Chaffetz pleading him to start an investigation on Trump, his top aides and Attorney General Jeff Sessions.

“The events of recent weeks also raise questions about whether President Trump breached his oath of office,” the letter read. “We have a solemn obligation under the Constitution to act as a check on the Executive Branch and to hold President Trump accountable. It is time to do our job.”