A prosecutor did not rule out the possibility Friday that the special counsel's office would bring additional charges against Paul Manafort for allegedly violating his September plea deal.

Andrew Weissmann, a top prosecutor working under Special Counsel Robert Mueller III, said his team was prepared to detail how Manafort, the onetime Trump campaign chairman, broke his plea agreement by lying to investigators. When asked by Judge Amy Berman Jackson whether the special counsel planned to charge Manafort over those allegedly false statements, Weissmann replied, “That determination has not been made yet.”

Berman Jackson set a Dec. 7 deadline for the special counsel to lay out Manafort's alleged lies. She also set Manafort's sentencing for March 5 but signaled the date could change as prosecutors and Manafort's defense lawyers duel over whether the plea agreement was breached.

“We may be able to accelerate it. We may have to put it off,” Berman Jackson said.

The developments came during a Friday morning hearing before Jackson. The proceeding marked the first time attorneys on both sides met in open court after prosecutors accused Manafort of lying to the special counsel's office and federal investigators, violating a September plea deal where he agreed to cooperate fully and truthfully with the government.

Manafort's defense lawyers have denied that he lied to investigators. Kevin Downing, a lead defense lawyer for Manafort, declined to comment after Friday's hearing.

In court, lawyers were at odds over how much prosecutors have discussed Manafort's alleged misstatements with Manafort's attorneys. Downing said there were “a lot of unknowns” as to what the U.S. intended to do, while Weissmann asserted that there had been “lengthy conversations with the defense.

Manafort has “committed federal crimes by lying to the Federal Bureau of Investigation and the Special Counsel's Office on a variety of subject matters, which constitute breaches of the agreement,” prosecutors said in a Monday court filing.

Manafort first entered into a plea deal with prosecutors in September, a day before jury selection was set to begin in a Washington, D.C., trial on charges related to his past foreign lobbying work for Ukraine. As part of the agreement, he pleaded guilty to two conspiracy counts, including one covering broad offenses related to his previous lobbying work and his effort to conceal income, and another related to the set of witness tampering allegations that landed him in jail this year.

In addition to the counts in Washington, D.C,. Manafort was found guilty on eight counts of financial fraud by an Alexandria, Virginia, federal jury in August. U.S. District Judge T.S. Ellis III of the Eastern District of Virginia plans to sentence Manafort in February.

Manafort, who is currently in a Virginia jail, did not attend Friday's hearing.

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