Parts of a court filing that were meant to be redacted by Manafort's legal team, were released publicly on Tuesday, CNN reported.
A major court filing error led to secret details of former Trump campaign chairman Paul ManafortPaul John ManafortManafort attorneys file response under seal to Mueller's lying allegations Russian lawyer who attended Trump Tower meeting charged in separate probe Manafort attorneys file answers to Mueller claims under seal MORE's criminal case leaking out into the public sphere on Tuesday.
Donald Trump's one-time presidential campaign chairman Paul Manafort admitted in a court filing Tuesday he provided polling data from the campaign to a Russian with ties to intelligence during the 2016 USA presidential race.
In those sections, Manafort's lawyers say he "conceded" having possibly discussed a Ukraine peace plan with Mr Kilimnik on more than one occasion.
Prosecutors have previously said they believe Kilimnik has ties to the military intelligence unit the GRU, which allegedly hacked the Democratic Party and leaked damaging emails while Manafort ran Trump's campaign operation. A new court filing says Manafort is suspected of having shared polling data with a business associate who has links to the Russian intelligence service.
Mueller could potentially bring new charges against Manafort.
A spokesman for Manafort's defence team declined to comment on Tuesday, but lawyers later filed a corrected version of the document.
It is to say that Manafort's lawyers' general characterization of Mueller's allegations about Manafort's conduct in the context of a dispute over whether Manafort violated his plea agreement or not offers a highly imperfect window into Mueller's understanding of that evidence and how it fits into the larger picture of interactions between the Trump campaign and the Russian state.
The court filing does not reveal when that meeting took place, but an unredacted section that follows highlights that it is "not uncommon, however, for a witnesses to have only a vague recollection about events that occured years prior" and that "these occurrences happened during a period when Mr. Manafort was managing a US presidential campaign and had countless meetings, email communications, and other interactions with many different individuals, and traveled frequently".
Manafort told a colleague in February - four months after he was indicted - he was in contact with a senior administration official through that time, prosecutors said.
The lawyers said Ukraine-related matters "simply were not at the forefront of Mr Manafort's mind during the period at issue".
Manafort agreed to cooperate with Mueller when he admitted to two conspiracy counts in Washington on September 14, a month after jurors convicted him in Virginia of tax and bank fraud.
The schedule for court filings over the matter was set at a conference on December 11, with the court outlining the dates by which each side would have to submit filings related to Manafort's alleged breach of his plea agreement.
The judge in DC federal court who has overseen his case, Amy Berman Jackson, gave him the opportunity to respond before she would hold a hearing about the facts of the situation. He is due to be sentenced in that case next month. In return, prosecutors said they would consider asking the judge for leniency at his eventual sentencing.