Ex-Trump aide Manafort violated plea deal by lying: Prosecutors

A day after special counsel Robert Mueller accused former Trump campaign manager Paul Manafort of lying, President Trump is again blasting the Russian Federation probe as a witch hunt.

In the new court filing, Mueller's team said that after Manafort agreed to truthfully cooperate with the investigation, he "committed federal crimes" by lying about "a variety of subject matters".

Both cases stemmed from Manafort's political work for the former pro-Russia president of Ukraine, and undisclosed lobbying work he admitted to carrying out on behalf of Ukraine in violation of USA law.

Manafort, who worked for the Trump campaign for almost six months in the middle of 2016, agreed to plead guilty to one count of conspiracy against the United States and another count of obstruction of justice in a deal to avert a second trial on money laundering and illegal lobbying charges.

"The Phony Witch Hunt continues, but Mueller and his gang of Angry Dems are only looking at one side, not the other", Trump tweeted. Earlier this month, there were mounting tensions between Mueller and Manafort over Manafort's apparent lack of cooperation with the investigation, multiple sources familiar with the matter told ABC News.

Without a pardon, Manafort could spend the rest of his life in prison, experts said.

The rupture in relations could hamper Mueller's ability to turn an insider against Trump in the investigation of Russian meddling in the 2016 election, and has raised questions about whether Manafort could be angling for a presidential pardon.

Though prosecutors can vacate Manafort's plea agreement, they may not want to do that yet because it would result in another lengthy trial.

Mueller: Manafort Lied During My Investigation, Voiding His Cooperation Agreement

"On balance, I think this is a much bigger blow to Manafort than the prosecution", Wu said.

Prosecutors did not provide details of the alleged lies but said they would do so prior to sentencing. The cases that Mueller's team brought against Manafort largely focused on his Ukrainian political consulting work, his U.S. lobbying over the last decade and the financial management of his business proceeds.

While Robert Mueller has been struggling to find links between the Trump campaign and WikiLeaks - that distributed emails and other documents, which Russian agents stole from Democratic computers before the 2016 presidential elections - Trump has been criticizing the special counsel.

Manafort was found guilty in August on eight-counts of tax and bank fraud.

Mueller and Manafort had come to the plea agreement in October, just before the case against the former Trump campaign chairman in D.C. was about to go to trial.

Manafort's lawyers have denied that he misled investigators.

Asked whether Trump is concerned about the final report that Mueller's team is expected to produce once the investigation wraps - and whether it might become public - Sanders said the president doesn't have "any concerns" about what it might say because "there was no wrongdoing by him".

But with prosecutors saying he breached the agreement, Manafort now faces serious repercussions such as the possibility of prosecution on additional charges including the 10 felony counts prosecutors dropped when he made the deal.