Judge agrees to postpone sentencing for Michael Flynn after unleashing a furious rebuke on him in court

President Donald Trump's first national security adviser, Michael Flynn, asked a federal judge to delay sentencing for lying to FBI agents about his contacts with Russia.

The retired U.S. Army lieutenant general pleaded guilty to lying to investigators in January 2017 about his contacts with Russian ambassador Sergey Kislyak during the presidential transition, and the judge blasted Flynn in court during his sentencing hearing.

"You were an unregistered agent of a foreign country while serving as the National Security Adviser to the president," said Judge Emmet Sullivan. "Arguably, this undermines everything this flag over here stands for. Arguably, you sold your country out."

However, Sullivan walked back those statements after a half-hour recess requested by Flynn, saying his contact with foreign agents took place before he was in the White House and clarified another remark.

"I'm not suggesting he committed treason," Sullivan said, after asking prosecutors if they had considered that charge. “Don’t read too much into the questions I asked."

After the recess, defense attorneys changed course and said they would take up Sullivan on his repeated offers to delay the sentencing.

The judge set a status hearing for March 13.

Flynn had agreed to cooperate with special counsel Robert Mueller, who said in sentencing documents that Flynn had provided "substantial" assistance to the investigation and at least two others, but he has since claimed the FBI tricked him into making misleading statements.

Trump, in a Tuesday morning tweet, appeared to encourage his close campaign aide to stick with those claims, which have been amplified by White House officials and the president's personal lawyers, during the sentencing hearing.

But his attorneys told the judge that Flynn did not believe he was trapped into lying and accepted full responsibility for his actions, and they did not wish to delay the sentencing hearing.

However, they changed their mind after Sullivan unloaded on Flynn, who offered to provide additional testimony to prosecutors in exchange for a lighter sentence.

Flynn has already met with investigators 19 times, according to prosecutors, and has also admitted to lying about his undisclosed lobbying for Turkey's government and other research work.

He resigned from the White House in February 2017, after serving just 24 days.