Donald Trump’s former national security adviser, Michael Flynn, has pleaded guilty after being charged with lying to the FBI over links to Russia.
It has also emerged that as part of a plea agreement, he has agreed to co-operate with an investigation led by special counsel Robert Mueller.
Mr Mueller and a team of prosecutors are looking into accusations of Russian meddling in last year’s presidential election and potential collusion by Mr Trump’s campaign.
ABC News reported that Mr Flynn was prepared to testify that Donald Trump directed him to make contact with Russians when he was a presidential candidate.
The report cited a confidante of Mr Flynn.
US stock indexes fell following the ABC report. Wall Street has recently been trading at record highs because of plans by President Trump to cut taxes.
White House lawyer Ty Cobb said: “Nothing about the guilty plea or the charge implicates anyone other than Mr Flynn.”
Mr Cobb described Mr Flynn as “a former Obama administration official” who was only at the White House for “25 days”.
Mr Flynn was charged with being dishonest about contacts with Russia’s ambassador to the United States, Sergey Kislyak.
When asked in court in Washington whether he wanted to plead guilty, the retired three-star general said: “Yes sir.”
A court paper said Mr Flynn “did wilfully and knowingly make materially false, fictitious, and fraudulent statements and representations”.
It added that Mr Flynn “falsely stated and represented to agents of the Federal Bureau of Investigation” his dealings with the Russian ambassador.
Mr Flynn said his guilty plea was “in the best interests of my family and of our country”.
“I accept full responsibility for my actions,” he said.
The charges related to events late last year, during the transition period between President Obama and President Trump, when the United States imposed sanctions on Russia, and when a United Nations Security Council resolution was pending.
Mr Flynn was interviewed by the FBI just days after Mr Trump’s inauguration on 20 January, before being forced to resign in February after White House officials claimed he had misled them about whether he had held discussions with Mr Kislyak.
Another former senior aide to Mr Trump, Paul Manafort, who ran his campaign for president for several months last year, was charged in October with conspiring to launder money, conspiracy against the United States and failing to register as a foreign agent of Ukraine’s former pro-Russian government.
Mr Manafort, who did not serve in Mr Trump’s administration, and a business associate who was charged with him, pleaded not guilty.
Mr Flynn is the first person who actually worked in the White House to be charged.
Mr Trump is said to have taken a particular interest in the Flynn investigation. Former FBI Director James Comey has claimed that during a private meeting in the Oval Office, Mr Trump asked him to consider ending the investigation into Mr Flynn.
Mr Comey said he was so unnerved by the meeting that he prepared an internal memo about it.
The assertion has been denied by the White House.
The dismissal of Mr Comey by the President in May precipitated the appointment of Mr Mueller as special counsel.