President Donald Trump has denied asking former FBI director James Comey to stop investigating his ex-national security adviser Michael Flynn.
Mr Comey testified before Congress in June that the president asked him if could see to "letting Flynn go".
Mr Comey said that request came a day after Mr Trump forced Flynn to resign his White House post.
In an tweet earlier, Mr Trump said: "I never asked Comey to stop investigating Flynn. Just more Fake News covering another Comey lie!"
I never asked Comey to stop investigating Flynn. Just more Fake News covering another Comey lie!
— Donald J. Trump (@realDonaldTrump) December 3, 2017
Flynn pleaded guilty on Friday to lying to the FBI and agreed to cooperate with special counsel Robert Mueller's investigation into Russian meddling in the 2016 election.
Mr Trump fired Mr Comey as FBI director in May.