The federal judge overseeing the still-pending sentencing of former national security adviser Michael Flynn has set a Wednesday afternoon deadline for the government to explain whether new developments in a related case should result in prison time for Flynn.

D.C. District Court Judge Emmet Sullivan ordered Flynn's lawyers, in turn, to file a response to the government's arguments no later than 5:00 p.m. on Thursday, adding, "the Court will not extend these filing deadlines."

The order comes shortly after prosecutors revealed they won't call Flynn to testify at the upcoming trial of his one-time business partner and now consider him to be an unindicted co-conspirator.

WHY DID FLYNN FIRE HIS LAWYERS?

Court documents unsealed Tuesday in federal court in Alexandria show prosecutors changed their minds about putting Flynn on the stand at next week's trial of Bijan Kian.

Flynn's lawyers have objected to the about-face, and say prosecutors wanted him to take the stand and admit things that weren't true. Flynn's sentencing had been postponed so Sullivan could take into account Flynn's level of cooperation at the Kian trial.

"On June 24, 2019, defense counsel represented to the Court that Mr. Flynn was scheduled to testify at the trial in the United States District Court for the Eastern District of Virginia before the Honorable Anthony J. Trenga," the order from Sullivan read. "On July 9, 2019, Judge Trenga issued an order unsealing certain court records ... the government is ORDERED to file a submission to this Court no later than 5:00 PM on July 10, 2019 explaining how the unsealed records in United States v. Rafiekian will impact the proceedings before this Court."

Flynn has been cooperating for months with federal prosecutors in a bid to avoid any prison time, but abruptly fired his law firm last week -- in a move that suggested he might contest the terms of his plea deal. Flynn, who attended a fireworks-filled sentencing hearing in December 2018, has consistently asked that Sullivan delay his sentencing while he continued his government cooperation.

"I'm not hiding my disgust, my disdain for this criminal offense," Sullivan said during that hearing, during which he briefly suggested Flynn could be guilty of treason before walking the idea back.

One of Flynn's new lawyers, Jesse Binnall, pointed out that prosecutors said explicitly at a June 13 hearing that they did not consider Flynn to be a co-conspirator in the case. Binnall said it's wrong for the government to reverse that assessment simply because they don't find his testimony to be useful.

FLYNN SAYS FBI PUSHED HIM NOT TO BRING A LAWYER TO FATEFUL WHITE HOUSE INTERVIEW

"The government's reversal also sounds an alarm of potential retaliation and may have ramifications for Mr. Flynn beyond this trial," Binnall wrote in a court document.

Kian is charged with illegally acting as a foreign agent. Prosecutors say Kian was acting at the Turkish government's behest when he persuaded Flynn to write a November 2016 op-ed piece critical of Fethullah Gulen, a cleric living in the U.S. who is a nemesis of Turkish President Recep Tayyip Erdogan.

The legal advice Flynn and Kian received about whether they were required to register as foreign agents — and its admissibility at trial — has been a major issue in pretrial proceedings.

After the op-ed piece ran, government lawyers contacted Flynn and Kian's joint business, Flynn Intel Group, and questioned whether they needed to register as foreign agents. Flynn Intel Group ultimately registered under the Foreign Agents Registration Act. But the indictment alleges that Kian knowingly made false statements to his lawyers and on the FARA registration form.

Binnall says that when Flynn made the FARA application, he thought at the time he was providing accurate information. Binnall said prosecutors wanted Flynn to admit that he knew the statements were false at the time he made them.

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"Mr. Flynn cannot give that testimony because it is not true," Binnall said.

Flynn pleaded guilty in December 2017 to lying about his contacts with Russians in the months between Trump's election and his inauguration in a separate case brought by then-Special Counsel Robert Mueller. Flynn had been an outspoken foreign policy adviser to Trump during the 2016 campaign and served briefly in the administration as national security adviser before questions about his dealings with Russia forced him to resign.

WAS MICHAEL FLYNN TARGETED?

Ahead of the December 2018 hearing, Mueller's team recommended that Flynn be spared jail time, citing his cooperation with the special counsel's probe of Russian activities during the 2016 election campaign.

Kian's lawyers, for their part, say the case against their client is built largely on information provided by Flynn and the case is weak because Flynn can't be trusted to tell the truth.

"The government has belatedly realized what should have been clear all along — Flynn is not to be believed," Kian's lawyers wrote.

Fox News' Bill Mears, Ronn Blitzer, and The Associated Press contributed to this report.