Paul Manafort lied about his relationship with an alleged Russian intelligence agent, even after agreeing to cooperate with Robert Mueller's investigation. A judge ruled Wednesday.

Manafort, the former president of Donald Trump's presidential campaign, violated his agreement by making false statements to the special council team, the FBI and a grand jury about his relations with Konstantin Kilimnik.

This finding means that Mueller's team is no longer forced to approve the lighter sentence promised to Manafort for his crimes when he agreed to cooperate with the investigators and tell them the truth. Manafort denied having lied.

Judge Amy Berman Jackson made the order Wednesday night in federal court in Washington DC.

Jackson said Mueller's team had established that Manafort had lied about three contentious issues: his interactions with Kilimnik, a payment he had received from a pro-Trump campaign group, and another unidentified investigation.

She added that Mueller's team had failed to establish that Manafort had lied on two other topics: his recent contacts with Trump administration officials and Kilimnik's role in a plot to obstruct the justice for which they had been charged.

Mueller is investigating Russia's interference in the 2016 presidential election, which, according to US intelligence, was intended to strengthen Trump's candidacy for the White House and any coordination between his agents and his team.

Manafort, 69, was accused by Mueller of lying about the fact that he had shared survey data on the 2016 election with Kilimnik, a former campaign colleague for politicians pro-Kremlin in Eastern Europe.

Manafort also allegedly misled investigators about the plans he was preparing with Kilimnik for a settlement of Russia's aggressive acts in Ukraine.

Kilimnik, 48, was trained at a university linked to the Russian military intelligence service, formerly known as the GRU, which allegedly led the Kremlin's efforts to disrupt the 2016 US elections.

Mueller also said earlier that Rick Gates, MP for Manafort for the Trump campaign, described Kilimnik as "a former Russian intelligence officer of the GRU." Kilimnik denies this characterization.

The special council decided to dismantle Manafort's plea in November, alleging that the former campaign president had violated the agreement by continuing to lie. Mueller said the lies were new crimes.

Manafort reportedly met Kilimnik twice in 2016. He forwarded the survey data to Kilimnik at a meeting held in August in New York, according to investigators. Mueller's team also discovered that Manafort met Kilimnik in Spain in 2017.

Manafort's lawyers firmly denied that they misled the investigators. They stated that he did not remember certain details and had strived to quickly clarify any discrepancies.

His attorneys did not deny that Manafort provided Kilimnik with the survey data, claiming that he had not lied about it, but that he was simply "unable to remember specific details before his memories are refreshed. "

As part of the plea deal reached last September, Manafort pled guilty to conspiring to defraud the United States and obstructing justice, in connection with unregistered lobbying activities for men pro-Russian policies. The other charges against him were dropped.

At that time, Manafort had been convicted of eight counts in a separate fraud case against him by Mueller in Virginia.