WASHINGTON (REUTERS) - US President Donald Trump's former campaign manager Paul Manafort breached his plea agreement with Special Counsel Robert Mueller's office by lying to prosecutors, a federal judge ruled on Wednesday (Feb 13).

The ruling concludes weeks of wrangling between Manafort's lawyers and the special counsel over whether he had intentionally lied to prosecutors, impeding their investigation into Russian interference in the 2016 US election and possible collusion between Russia and the Trump campaign.

US District Judge Amy Berman Jackson, who is overseeing the Manafort case in a Washington court, found there was a "preponderance" of evidence that Manafort lied on three different topics, including his communications with his former business partner Konstantin Kilimnik, but she cleared Manafort of allegations that he intentionally lied on two other subjects.

The ruling follows last week's release of a court transcript that showed Mueller's team believed Manafort's alleged lies were central to their investigation into potential collusion, which Trump and Russia have both denied.

The investigation appears focused on a meeting held at the height of the election campaign between Manafort and Kilimnik, whom prosecutors say has ties to Russian intelligence, according to the court filing.

Mueller contends that Manafort lied about the number of times he and Kilimnik discussed a "Ukrainian peace plan" - a reference to a proposal that would result in the US lifting sanctions on Russia, one of the Kremlin's top objectives.

In a court filing ahead of Wednesday's ruling, Manafort's lawyers repeated their argument that their client never intentionally lied to prosecutors and stressed that he corrected any mistakes once they were pointed out to him.