Attorneys for Manafort inadvertently disclosed the allegation in a court filing on Tuesday.
Though there was no comment from Manaford's legal team, a new, corrected filing was quickly posted on the docket that no longer allowed the public to see the redacted paragraphs, The Hill reported.
According to the filing, Manafort discussed a Ukrainian peace plan with his close Russian-intelligence-linked associate, Konstantin Kilimnik.
Mueller, who is investigating Russia's interference in the 2016 election, said in a court filing in March past year that the Federal Bureau of Investigation assesses that Kilimnik "has ties to a Russian intelligence service and had such ties in 2016".
Lawyers for Paul Manafort apparently mistakenly filed a court document Tuesday that revealed redacted material- including accusations Manafort shared 2016 campaign polling data with a Russian national linked to the Kremlin.
Previously, the special counsel's office outlined five areas in which they believe Manafort lied, including about his contact with Kilimnik, who is of interest to the Mueller investigation, and about his communication with White House officials as recently as previous year, but redacted some details of what they know and how they know it. This is a common error in court filings, cleaned-up confidential government documents intended for release, and releases under various countries' freedom of information acts.
Kilimnik has always been suspected to be central to Mueller's investigation into Russian influence in the 2016 presidential election.
According to the court filing, Mueller also accused Manafort of lying about discussing a Ukrainian peace plan with Kilimnik during the 2016 campaign.
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Manafort provided "complete and truthful information to the best of his ability", the lawyers wrote in the 10-page filing. There are two known meetings during the campaign between Manafort and Kilimnik.
Manafort told a colleague in February - four months after he was indicted - that he was in contact with a senior administration official through that time, prosecutors said in accusing him of lying. Manafort also was convicted last summer of financial crimes in a Virginia trial just outside Washington.
Manafort sent Kilimnik, a former Russian military intelligence official, an email in April 2016, shortly after joining the campaign, suggesting that he sought to use his new position as leverage with Deripaska. The second example identified by the Special Counsel is hearsay purportedly offered by an undisclosed third party and the defense has not been provided with the statement (or any witness statements that form the basis for alleging intentional falsehoods).
The Russian citizen was a long-time employee of Manafort's political consulting firm and had done extensive lobbying work for him in Ukraine on behalf of the country's then pro-Russian President, Viktor Yanukovych.
Judge Amy Berman Jackson has ordered the government to provide a detailed factual basis about Manafort's lies, which is due January 14. Manafort's filing sheds little light on that transaction.
Jackson has scheduled Manafort's sentencing for March 5, but the judge said she first wanted to determine whether he did breach the plea agreement.
Manafort reached the plea agreement with Mueller in September after a jury found him guilty of eight charges of tax evasion and bank fraud by a jury in the USA state of Virginia in August.