Former Trump national security and campaign adviser Michael Flynn will not be sentenced for lying to the FBI until March.

A federal judge agreed to delay the sentencing of the former Trump official after signaling to Flynn and his attorneys that he was prepared to send Flynn to prison unless he learned more about his cooperation with special counsel Robert S. Mueller III.

Flynn admitted to Judge Emmet Sullivan in a Washington courtroom on Tuesday that he knew it was a crime when he lied to the FBI in January 2017.

Flynn told Sullivan that he was “aware” that he was committing a crime when he lied to the FBI and declined to accept the judge’s offer to withdraw his guilty plea. But after a tirade in which the judge appeared to question whether Flynn could have been charged with treason — he later walked back those questions and told the courtroom audience to disregard them — Flynn’s attorneys asked Sullivan to delay the sentencing. Mueller’s prosecutors agreed.

Flynn walked into the courtroom for his sentencing Tuesday at roughly 11 a.m. with a fresh haircut wearing a blue suit, crisp white shirt, and red-and-blue striped tie.

Sullivan unleashed a tirade against Flynn, saying that he “sold … out” his country.

“You were an unregistered agent of a foreign country while serving as the national security adviser to the president of the United States,” Sullivan said.

“Arguably this undermines everything this flag over here stands for,” he said, pointing behind him to a flag in the courtroom.

Mueller and his team of prosecutors recommended in a court memo earlier this month that Flynn should not face prison time.

Prosecutors commended Flynn, a retired three-star general in the U.S. Army, for “accepting responsibility in a timely fashion” for lying to the FBI about conversations he had with the Russian ambassador to the U.S. during Trump’s transition to the White House and then “substantially assisting the government” after he pleaded guilty last December.

Flynn attended 19 meetings with the special counsel and handed over documents and communications that helped prosecutors track down leads in multiple investigations, they wrote in the sentencing recommendation memo.

Many legal experts believe those offshoot investigations could implicate the president’s son-in-law and senior White House adviser, Jared Kushner, as well as other officials on the Trump transition team after he won the 2016 election but before he took the oath of office.

Flynn’s attorneys had argued for a lenient sentence that included probation and community service since Flynn exhibited “genuine contrition for the uncharacteristic error in judgment that brought him before this court.” Flynn’s lawyers also cited the former three-star U.S. Army lieutenant general’s clean record in the military that spans decades.

More details about Flynn’s crimes emerged Monday evening, when Mueller’s team released a memo from January 2017 detailing his conversation with FBI officials at the White House in which he lied to the agents. In that conversation, Flynn denied that he had made policy requests in his conversations with Sergei Kislyak, who was then serving as Russian ambassador to the U.S.

Flynn also pleaded guilty to lying about his lobbying work for the Turkish government. The Department of Justice indicted his two Turkish lobbying business associates on Monday for conspiracy and acting as foreign agents. The indictment spells out in sharp detail how Flynn was paid hundreds of thousands of dollars to allegedly lobby for the Turkish government through a conduit.

President Donald Trump tweeted his support for Flynn before his sentencing Tuesday morning and once again denigrated Mueller’s investigation, which remains ongoing but has already elicited seven guilty pleas or verdicts from people such as the president’s former campaign chairman, Paul Manafort, and former personal lawyer, Michael Cohen.

The Washington rumor pool has stirred for nearly a year with gurgles that Trump could pardon his former campaign and national security adviser.

“Good luck today in court to General Michael Flynn,” Trump tweeted.

“Will be interesting to see what he has to say, despite tremendous pressure being put on him, about Russian Collusion in our great and, obviously, highly successful political campaign. There was no Collusion!” Trump added, though Flynn’s sentencing deals with charges related to lying to the FBI, not with the Trump campaign’s potential collusion with Russia.

Good luck today in court to General Michael Flynn. Will be interesting to see what he has to say, despite tremendous pressure being put on him, about Russian Collusion in our great and, obviously, highly successful political campaign. There was no Collusion!

— Donald J. Trump (@realDonaldTrump) December 18, 2018

The president, conservative lawmakers and pundits have latched on to the revelation that Flynn was not warned that lying to FBI agents was a federal crime, a point made by his lawyers in a memo filed earlier this month.

Mueller’s prosecutors, apparently peeved by that public noise, responded sharply in a separate memo filed with the court on Friday.

“A sitting National Security Advisor, former head of an intelligence agency, retired Lieutenant General, and 33 year veteran of the armed forces knows he should not lie to federal agents,” Mueller’s prosecutors wrote.

Sullivan asked Flynn and his lawyers multiple times on Tuesday whether they wanted to challenge the circumstances of his conversation with the FBI that led to the charges or postpone his sentencing, BuzzFeed News reported.

“No, your honor,” Flynn responded.

Sullivan’s insistence was an apparent effort to make clear that Flynn was accepting his guilty plea because he was guilty, not because he felt he had been entrapped.

Judge Sullivan is making sure it’s abundantly clear that Michael Flynn is pleading guilty because he’s guilty. That he lied to the FBI, that he knew it was wrong to lie to the FBI.

— Ryan J. Reilly (@ryanjreilly) December 18, 2018

Mueller’s investigation remains ongoing as the special counsel tries to pin down more evidence about the Trump’s campaign, transition and inauguration teams’ ties to Russia and whether the president obstructed justice when he fired former FBI Director James B. Comey.

Comey has answered questions twice in the last two weeks from a joint panel of lawmakers from the House Oversight and Judiciary Committees. Those conversations have been behind closed doors. Comey assented to answering lawmakers’ questions in private only after the Republican chairmen of the committees agreed to publicly release transcripts of the conversations.