‍Special Counsel Robert Mueller's team told a U.S. judge on Saturday that President Donald Trump's former campaign chairman Paul Manafort "repeatedly and brazenly" broke the law, and argued he did not deserve leniency at sentencing.

The recommendation from Mueller, who is investigating Russia's role in the 2016 U.S. presidential election and whether Trump's campaign conspired with Moscow, increases the likelihood that Manafort will spend the rest of his life behind bars.

Manafort pleaded guilty in a federal court in Washington, DC last September to conspiracy against the U.S., a charge that includes a range of conduct from money laundering to unregistered lobbying, and conspiracy to obstruct justice for attempts to tamper with witnesses.

He can be sentenced up to five years for each count, for a statutory maximum of 10 years.

While Mueller did not recommend a specific sentence he portrayed Manafort as a "hardened" criminal who was at risk of repeating criminal behavior if released from prison.

As part of an earlier plea deal with Mueller, the special counsel dropped five other charges and Manafort agreed to cooperate with prosecutors. But Mueller's team in November accused Manafort of violating the agreement by repeatedly lying to prosecutors on subjects including his interactions with a business partner they have said has ties with Russian intelligence. The judge this month ruled Manafort had breached the deal.

"For over a decade, Manafort repeatedly and brazenly violated the law," Mueller's office said in a sentencing memorandum released by the court on Saturday.

"His criminal actions were bold, some of which were committed while under a spotlight due to his work as the campaign chairman and, later, while he was out on bail from this court."

Manafort, a 69-year-old veteran Republican political consultant who earned millions of dollars working for pro-Russian politicians in Ukraine, faces up to 25 years in prison under federal sentencing guidelines in a second case in Virginia in which he was convicted last year of financial crimes.