Federal prosecutors urged a judge Tuesday to sentence former national security advisor Michael Flynn later this month to anywhere from zero to six months in jail for lying to federal agents about his contacts with a Russian diplomat shortly before the inauguration of President Donald Trump.

The recommendation was a sharp reversal for prosecutors, who previously had asked that Flynn get a sentence with no jail time in recognition of his extensive help with "several ongoing investigations" following his guilty plea in late 2017.

In their new court filing — which comes more than a year after Flynn's original sentencing hearing was dramatically aborted — prosecutors cited the "serious nature of" the retired Army lieutenant general's crime and "his apparent failure to accept responsibility" for his actions.

They also accused him of trying to "thwart the efforts" of prosecutors to convict other people, even as he assisted them in other criminal cases.

The new recommendation comes after months of efforts by Flynn and his defense lawyers to effectively undo his guilty plea in the case by arguing that prosecutors had withheld evidence from him, and that the FBI had misled Flynn.

"In light of the complete record, including actions subsequent to December 18, 2018, that negate the benefits of much of the defendant's earlier cooperation, the government no longer deems the defendant's assistance 'substantial,' prosecutors wrote.

"The government also does not believe the defendant should receive credit for acceptance of responsibility," prosecutors wrote. "Indeed, the government has reason to believe, through representations by the defendant's counsel, that the defendant has retreated from his acceptance of responsibility in this case regarding his lies to the FBI."

Flynn currently is scheduled to be sentenced by Judge Emmet Sullivan on Jan. 28 in U.S. District Court in Washington, D.C.

"The defendant is now scheduled to be sentenced almost exactly three years from the date of his primary criminal conduct – lying to the FBI – and the intervening years have included periods where the defendant has sought to assist and aid the government, and periods where the defendant has sought to thwart the efforts of the government to hold other individuals, principally Bijan Rafiekian, accountable for criminal wrongdoing," prosecutors wrote in their filing.

Rafiekian, a former business associate of Flynn's, was accused of unlawfully lobbying on behalf of Turkey.

Rafiekian was convicted last summer on two counts of violating the Foreign Agent Registration Act. Flynn was supposed to testify against Rafiekian at trial, but prosecutors scrapped that plan after saying they did not necessarily believe Flynn's account of how he came to make an inaccurate FARA filing.

Rafiekian's conviction was overturned and the indictment against him dismissed in September by a federal judge who said there was insufficient evidence to sustain the case.

Flynn's defense lawyer, Sidney Powell, had no immediate comment about the new sentencing recommendation.

Flynn pleaded guilty in December 2017 to lying to FBI agents about the nature of his discussions with Russia's ambassador to the United States in the weeks leading up to Trump's inauguration in January 2017.

He resigned in February 2017 after allegedly misleading Vice President Mike Pence about what he and the Russian diplomat talked about.

Flynn had falsely told Pence he had not discussed U.S. sanctions against Russia, which led Pence to defend him in television interviews. In fact, Flynn had discussed those sanctions.

He originally was set to be sentenced in December 2018.

But that sentencing was cut short after Sullivan warned him he might send Flynn to jail if he did not postpone the proceeding.

"Arguably you sold your country out," Sullivan said at that hearing, where he noted Flynn's failure to disclose lobbying work for Turkey.