Paul Manafort's lawyers accidentally unsealed a slew of new details about the lies Manafort has been accused of telling prosecutors working for the special counsel Robert Mueller after agreeing to cooperate in the Russia investigation.

Manafort's lawyers revealed that Mueller has accused him of sharing confidential polling data from the Trump campaign with the former Russian military intelligence officer Konstantin Kilimnik.

They also revealed that Mueller has accused Manafort of misleading prosecutors about his knowledge of a pro-Russia "peace plan" that was floated during the campaign and in the early days of the Trump administration.

Manafort's lawyers did not issue a full-throated denial of Mueller's allegations at any point.

Instead, they wrote that any misstatements on Manafort's part, "to the extent they occurred at all, were not intentional."

Lawyers representing Paul Manafort, the former chairman of President Donald Trump's 2016 election campaign, made a formatting error in a new court filing that accidentally revealed more details about Manafort's alleged lies to prosecutors after he struck a plea deal with the special counsel Robert Mueller.

The filing came in response to a December court filing from Mueller's office, in which prosecutors said Manafort told "discernible lies" about several topics.

They offered few details on the nature of the alleged lies, but they elaborated on the specific topics they claim Manafort misled prosecutors about. They included:

His interactions with Konstantin Kilimnik, a former Russian intelligence operative who was charged, along with Manafort, with obstruction of justice last year.

Kilimnik's role in the alleged conspiracy to obstruct justice by trying to influence the testimony of two witnesses last February.

A $125,000 payment made to a firm in 2017 related to a debt that Manafort had incurred.

His communications with Trump administration officials. According to prosecutors, Manafort told them that he only spoke with certain individuals before they joined the administration or after they left, but those statements were inconsistent with the truth. In fact, prosecutors said, Manafort authorized someone on May 26 to speak with an administration official on his behalf. The filing also pointed out that Manafort said in February that he had been in touch with a senior administration official until that month. And a review of the former Trump campaign chief's electronic documents revealed additional contacts with administration officials, prosecutors said.

Information that was "pertinent to another Department of Justice investigation." Prosecutors said Manafort first gave them information relevant to the investigation when he met with Mueller's team prior to pleading guilty. But they said he gave a "different and exculpatory version of events" after agreeing to cooperate.

Read more: Prosecutors say Paul Manafort breached his plea deal by telling 'discernible lies' after agreeing to cooperate

What Manafort's lawyers accidentally revealed

Paul Manafort. Thomson Reuters

In Tuesday's filing, Manafort's lawyers accidentally revealed that prosecutors allege Manafort shared Trump campaign polling data with Kilimnik.

They wrote that Manafort did not intentionally mislead investigators about the issue. Instead, they wrote, such matters "simply were not at the forefront of Mr. Manafort's mind during the period at issue and it is not surprising at all that Mr. Manafort was unable to recall specific details prior to having his recollection refreshed."

According to the filing, Mueller’s office also says Manafort "conceded" that he may have discussed a Ukraine peace plan with Kilimnik on more than one occasion, and that Manafort "acknowledged" that he and Kilimnik met when both men traveled to Madrid.

In another redacted section, Manafort's lawyers wrote that during a proffer session with Mueller's team in September, Manafort told prosecutors that "he would have given the Ukrainian peace plan more thought, had the issue not been raised during the period he was engaged with work related to the presidential campaign."

At the time, his lawyers wrote, "issues and communications related to Ukrainian political events" weren't on Manafort's mind.

The US intelligence community has concluded that Russia intervened in the 2016 US election with the specific purpose of sowing discord and tilting the race in Trump's favor. A key pillar in Mueller's Russia probe examines whether the Trump team offered anything to the Kremlin in exchange for its help during the election.

Read more: The Supreme Court handed Mueller a victory in his mysterious grand-jury subpoena fight

Along that thread, prosecutors are said to be examining a Russia-Ukraine "peace plan" that Michael Cohen, Trump's former lawyer and longtime fixer who is now cooperating with Mueller, sought to push through in the early days of the Trump administration.

The plan Cohen, the Russian-born businessman Felix Sater, and the Ukrainian politician Andrey Artemenko pushed would have had the US lift sanctions on Russia in exchange for Moscow withdrawing its support for pro-Russia separatists in eastern Ukraine. It would also have allowed Russia to maintain control over the territory of Crimea, which it annexed in 2014.

Manafort surfaced as a figure of interest for prosecutors when details began spilling out during the 2016 campaign about his ties to pro-Russian interests in Ukraine.

Investigators also began digging into whether Manafort worked as a conduit between the campaign and Russia to mitigate his mounting financial debts to wealthy Russians aligned with the Kremlin. Among those is the Russian oligarch Oleg Deripaska, who is close allies with Kilimnik.

Manafort is known to have offered Deripaska "private briefings" through Kilimnik about the campaign at the height of the election in an effort to resolve his debts to the aluminum magnate. In addition to communicating via email, Manafort and Kilimnik, who had worked together for years for pro-Russian Ukrainian interests, also met several times during the campaign.

Later in the filing, Manafort's lawyers addressed Mueller's contention that Manafort lied about a $125,000 payment made to a firm in 2017 related to a debt that he had incurred. "The Government has indicated that Mr. Manafort's statements about this payment are inconsistent with those of others, but the defense has not yet received any witness statements to support this contention," they wrote.

In response to prosecutors' claims that Manafort misled them about authorizing someone on May 26 to speak with an administration official on his behalf, Manafort's lawyers wrote that the claim relates to a text message from a third-party asking permission to use Manafort's name as an introduction in the event that the third-party met Trump.

"This does not constitute outreach by Mr. Manafort to the President," his lawyers said.

They added that "the second example" identified by Mueller "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 of alleging intentional falsehoods)."

Manafort's team did not issue a full-throated denial of prosecutors' claims. Instead, they said "any alleged misstatements, to the extent they occurred at all, were not intentional."