Russia investigation: Manafort pleads not guilty, September trial date set

Manafort had previously pleaded not guilty in the case but prosecutors for Mueller brought a second indictment last week, requiring him to formally enter a second plea. Manafort is accused of acting as an unregistered foreign agent and directing an international money-laundering conspiracy.

Manafort and his long-time business associate, Rick Gates, were originally indicted in the Mueller investigation last year, in connection to consulting work they did in Ukraine. In the 31-page indictment handed down by Mueller's office, federal prosecutors accused Manafort and Gates of conspiring against the United States, conspiring to launder money and working as unregistered foreign agents.

Both men pleaded not guilty last year, but Gates changed his plea to guilty on a pair of charges last week: making false statements and conspiring against the United States.

In a statement obtained by the New York Times last week, Manafort said he had no plans to change his plea.

"I had hoped and expected my business colleague would have had the strength to continue the battle to prove our innocence," Manafort said. "For reasons yet to surface, he chose to do otherwise. This does not alter my commitment to defend myself against the untrue, piled-up charges contained in the indictments against me."

During Wednesday's hearing, Judge Amy Berman Jackson reprimanded Manafort for making the public statement about Gates' plea. The judge said it violated her gag order.

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