A federal judge on Tuesday set a Dec. 18 sentencing hearing for Michael Flynn, the former national security adviser who pleaded guilty in 2017 to lying to federal investigators about his contacts with the Russian ambassador during the latest presidential transition.

U.S. District Judge Emmet Sullivan of the District of Columbia described the sentencing date as tentative, saying it "may be changed." But in scheduling the sentencing hearing, Sullivan showed he was eager to bring an end to Flynn's prosecution.

Flynn's new defense lawyer, Sidney Powell, had argued in the buildup to Tuesday's hearing that a sentencing date should not be set. Powell, who was hired in June after Flynn fired his former defense team at Covington & Burling, said she was still reviewing documents in the case and "working with prior counsel to tie up some loose ends."

Prosecutors had recommended a late October or early November sentencing. But when Sullivan suggested Dec. 18 on Tuesday, prosecutor Brandon Van Grack said, "that date works for the government."

Flynn first appeared for sentencing in December, but the hearing was derailed when Sullivan signaled he would order the former national security adviser and retired general to serve prison time. Prosecutors at the time had backed Flynn's request for leniency.

With his decision to hire Powell, Flynn adopted a more aggressive posture toward prosecutors, prompting speculation that he would seek to withdraw his guilty plea. In the buildup to Tuesday's hearing, Powell accused the the special counsel team of withholding exculpatory information from Flynn, in a court filing that leaned heavily on conspiracy theories that have stirred up right-wing criticism of the Russia investigation.

Van Grack, who prosecuted Flynn as a member of former Special Counsel Robert Mueller III's team, hinted Tuesday the Justice Department would no longer support Flynn's request to avoid prison time. Prosecutors, he said, would "refile the appropriate paperwork" concerning Flynn's sentence ahead of the December hearing.

Sullivan will take briefing over the next several weeks from the lawyers about Flynn's allegations of prosecutorial misconduct. Flynn's attorneys said they did not anticipate filing a motion to withdraw the plea, but rather would argue that the charges should be dismissed for alleged misconduct.

"I can't say right now exactly where it's headed. But I don't think it's going to be a motion to withdraw the plea," Powell said Tuesday.

Powell has alleged members of the prosecution team suppressed evidence that might have been helpful to Flynn "while at the same time putting excruciating pressure on him to enter his guilty plea and manipulating or controlling the press to their advantage to extort that plea."

Since taking up Flynn's case, Powell has pushed to delay the retired general's sentencing. In a court filing last month, Powell said she was still working with Flynn's former defense lawyers to tie up some loose ends.

Challenging Powell's claims, prosecutors said in court filings that the "government has exceeded its discovery and disclosure obligations" in Flynn's case.