US President Donald Trump says he never asked former FBI director James Comey to stop investigating former national security adviser Michael Flynn.
Flynn is the first member of Mr Trump's administration to plead guilty to a crime uncovered by special counsel Robert Mueller's investigation into Russian attempts to influence last year's US presidential election. Mr Trump fired Mr Comey from his post in May.
"I never asked Comey to stop investigating Flynn. Just more Fake News covering another Comey lie!" Mr Trump tweeted.
Mr Trump tweeted on Saturday that he fired Flynn because of not just his lies to Vice President Mike Pence, but to the FBI. He had previously said the dismissal was only related to Flynn's conversations with Mr Pence - not the FBI.
Around the time of Flynn's dismissal, Mr Comey has claimed Mr Trump asked him to end the investigation into Flynn.
The tweet raised eyebrows, with some in the legal community saying if Mr Trump knew Flynn lied to the FBI and then pressured Mr Comey not to investigate him, that would be problematic.
Mr Trump's tweet "absolutely bolsters an obstruction of justice charge", said Jimmy Gurule, a former federal prosecutor and a law professor at Notre Dame University.
"It is evidence of the crucial question of whether Mr Trump acted with a corrupt intent."
Mr Trump's personal lawyer has since taken responsibility for the tweet.
In an interview on Sunday with news site Axios, John Dowd said the tweet was "my mistake" and that he drafted the tweet that raised more questions about whether there had been attempts to obstruct the Russia investigation.
"I'm out of the tweeting business," Mr Dowd told Axios. "I did not mean to break news."
Reuters / Newshub.