President Trump’s former national security adviser Michael Flynn fired his attorneys ahead of his sentencing.

“General Flynn has notified the undersigned that he is terminating Covington & Burling LLP as his counsel and has already retained new counsel for this matter,” his attorneys said in a court filing Thursday.

Sentencing in Flynn’s case has not yet been scheduled, and it was not immediately clear whom Flynn had retained to represent him in court.

A judge later denied the attorneys' request to withdraw from his case.

Flynn pleaded guilty in December 2017 for lying to the FBI about his conversations with then-Russian ambassador to the U.S. Sergey Kislyak. Flynn asked Russia not to escalate tensions with the U.S. when the Obama administration imposed sanctions on Russia for interfering in the 2016 election.

Flynn was scheduled to be sentenced in December 2018, but it was postponed when a federal judge suggested it wait until he was done cooperating with special counsel Robert Mueller’s investigation.

The former Trump adviser has also admitted to lobbying on behalf of the Turkish government during the 2016 election without registering as a foreign agent with the Justice Department. He was not charged in the case, but two of his business partners were. Flynn is cooperating with prosecutors on the investigation.