A US District Court judge on Friday tentatively set a sentencing date of March 5 for Paul Manafort, the former campaign manager of President Donald Trump.
Manafort, 69, pleaded guilty in September to one count of conspiracy and another of obstruction of justice and agreed to cooperate with Special Counsel Robert Mueller's probe of possible collusion between the Trump campaign and Russia.
But the special counsel's office said this week that Manafort had violated the plea agreement by lying to investigators.
In court on Friday, prosecutors did not disclose what Manafort had allegedly lied about but were told by the judge to do so by December 7 to give his defense team time to respond.
They did not rule out out the possibility of filing additional charges against the veteran Republican political operative.
"Whether there will be additional charges, that determination has not been made," said Andrew Weissmann, an attorney with the special counsel's office.
US District Court Judge Amy Berman Jackson set March 5 as a tentative date for sentencing on the conspiracy and obstruction charges but said "we may have to put it off."