WASHINGTON — Special counsel Robert Mueller III told a judge Friday that Paul Manafort, President Donald Trump's former campaign chairman, told "multiple discernible lies" during interviews with prosecutors, including about his contacts with an employee who is alleged to have ties to Russian intelligence.

The allegations came in a new court filing by the special counsel that pointed to some of the questions prosecutors have been asking a key witness in their closely-held investigation into Russian interference in the 2016 campaign.

Mueller's prosecutors filed a portion of the document under seal and redacted other key points from view.

But they said that Manafort had told numerous lies in five different areas, including about his contacts with Konstantin Kilimnik, a Russian employee of Manafort's political consulting firm who prosecutors have said has Russian intelligence ties. Manafort met twice during the campaign with Kilimnik.

Manafort was convicted of tax and bank fraud charges in Virginia in August. He pleaded guilty in September to additional charges, including conspiring to defraud the United States by hiding years of income and failing to disclose lobbying work for a pro-Russian political party and politician in Ukraine.

That plea helped him avoid a second trial in Washington and offered the former Republican operative the hope of some leniency in sentencing — provided he cooperated with prosecutors and provided truthful testimony to investigators.

However, Mueller's team informed the judge last week that they believed Manafort had breached the agreement by lying to them repeatedly.

Prosecutors said they would detail his "crimes and lies" for U.S. District Judge Amy Berman Jackson.

Manafort's lawyers have said that Manafort did not believe he lied or violated the deal.

Manafort, 69, is currently jailed in Alexandria, Virginia.

Manafort is one of five former Trump campaign aides who have pleaded guilty to crimes as part of the special counsel investigation. As the campaign's former chairman and a top aide from March to August 2016, Manafort is viewed as a key firsthand witness for Mueller as he explores contacts between Trump associates and Russians.

Manafort attended a meeting with a Russian lawyer at Trump Tower arranged by Donald Trump Jr. after the president's son was told the lawyer would share damaging information about Democratic candidate Hillary Clinton. And he was at Trump's side as WikiLeaks released thousands of emails stolen from the Democratic Party in July 2016.

He also has extensive connections to business executives and politicians in the former Soviet Union, due to his years as an international political consultant, particularly his work for a Russia-backed president of Ukraine.