President Donald Trump's former personal lawyer says he's providing "critical information" to special counsel Robert Mueller's investigation into Russian interference in the 2016 US election.
Michael Cohen, who pleaded guilty to campaign finance and other charges last month, said on Thursday he was providing the information to prosecutors without a cooperation agreement.
Trump's longtime fixer-turned-foe could be a vital witness for prosecutors as they investigate whether Trump's campaign coordinated with Russians.
For more than a decade, Cohen was Trump's personal lawyer, and he was a key power player in the Trump Organisation and a fixture in Trump's political life.
Cohen pleaded guilty in August to eight federal charges and said Trump directed him to arrange payments before the 2016 election to buy the silence of porn actress Stormy Daniels and a former Playboy model who had both alleged they had affairs with Trump.
It was the first time any Trump associate implicated Trump himself in a crime, though whether - or when - a president can be prosecuted remains a matter of legal dispute.
On Thursday night, Cohen tweeted: "Good for (at)MichaelCohen212 for providing critical information to the (hash)MuellerInvestigation without a cooperation agreement. No one should question his integrity, veracity or loyalty to his family and country over (at)POTUS (at)realDonaldTrump."
The tweet was deleted almost immediately and was later reposted by his lawyer, Lanny Davis, who said he wrote the tweet for Cohen and asked him to tweet it because he has a "much larger following."
ABC News, citing sources familiar with the matter, said Cohen was questioned about Trump's dealings with Russia, including whether members of the Trump campaign worked with Russians to try to influence the outcome of the election.
The president has continued a very public battle against the Mueller investigation, repeatedly calling it a politically motivated and a "rigged witch hunt."
He has said he is going to declassify secret documents in the Russia investigation, an extraordinary move that he says will show that the investigation was tainted from the start by bias in the Justice Department and FBI.
Australian Associated Press
