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President Donald Trump's former campaign chairman Paul Manafort shared campaign polling data with a Russian associate linked to Russian intelligence services — and then lied about it to federal investigators, according to court papers filed Tuesday.

The disclosure was made by Manafort's lawyers in a poorly redacted section of court papers that were filed to rebut the special counsel's allegations that he lied to federal investigators.

The lawyers revealed that Manafort was not truthful about providing polling data related to the 2016 presidential campaign to Konstantin Kilimnik.

The document does not say when the polling information was shared or if the information was proprietary.

Kilimnik was charged with obstruction of justice last June for alleged witness tampering in a case against Manafort. Kilimnik has denied having any links to Russian intelligence. His whereabouts are unknown.

Last August, Manafort was convicted of bank and tax fraud charges. He later agreed to cooperate with special counsel Robert Mueller's office to avoid trial in a separate case on financial fraud charges.

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But Manafort broke the cooperation agreement by telling multiple lies to investigators on a host of topics, including his contacts with Trump administration officials and Kilimnik's role in the effort to coerce witness testimony, according to the special counsel.

In the court papers filed Tuesday, Manafort's lawyers also accidentally revealed that Manafort and Kilimnik discussed a "Ukraine peace plan" on more than one occasion. The Ukraine and Russia have been embroiled in a simmering conflict since 2014 when Russia annexed Crimea. The documents do not offer any details on the plan discussed by Manafort and Kilimnik.

The court papers also say Manafort initially told investigators that he hadn't met with Kilimnik in Madrid but the longtime GOP operative later admitted to the meeting after being told Kilimnik was there the same day.

The documents do not say when the meeting took place.

In another section that was supposed to be redacted, Manafort's attorneys offered new details about Mueller's allegations that the ex-campaign chairman lied about contacts with the Trump administration.

The lawyers said that on May 26, 2018, Manafort had "a text message from a third-party asking permission to use Mr. Manafort's name as an introduction in the event the third-party met the President."

The documents do not say who Manafort was communicating with. But Manafort's lawyers wrote, "This does not constitute outreach by Mr. Manafort to the President."

The accidental disclosures were made in a 10-page court filing arguing that Manafort never intentionally misled federal investigators.

Manafort "provided complete and truthful information to the best of his ability" over the course of 12 meetings with federal prosecutors and FBI agents, his lawyers said in the court filing.

"He attempted to live up to the requirements of his cooperation agreement and provided meaningful cooperation relating to several key areas under current government investigation," the court papers added.

The lawyers blamed Manafort's misstatements on the mental toll of living in solitary confinement, an inability to prepare for his meetings with federal investigators, and having to awake before dawn on the days he spoke with FBI agents and prosecutors.

Manafort has severe gout and is suffering from depression and anxiety due to limited contact with his family, according to his lawyers.

"While his physical safety is of primary concern, it is important to note that the conditions of Mr. Manafort's confinement have taken a toll on his physical and mental health," the court filing says.

But Manafort's attorneys did not request a hearing to determine whether or not he lied. The court ordered Mueller's office to respond to the defense document by Jan. 18.