Ex-Trump top aide Paul Manafort pleads not guilty, faces Sept. 17 trial
Paul Manafort (Youtube)

U.S. President Donald Trump's former campaign manager Paul Manafort pleaded not guilty on Wednesday to a new indictment brought against him in the investigation into alleged Russian meddling in the 2016 election and will face trial in September.

Special Counsel Robert Mueller, who is running the Russia probe, is dialing up the legal pressure on Manafort, who has not opted to cooperate with investigators.

Manafort's former business partner Rick Gates, another Trump ex-campaign aide, decided last week to cooperate with the investigation.

Manafort is facing two separate indictments on an array of charges, including conspiracy to launder money, filing false tax returns and failing to register as a foreign agent for lobbying work for the pro-Kremlin Ukrainian government of former President Viktor Yanukovych.

U.S. District Court Judge Amy Berman Jackson set Manafort's trial to start Sept. 17 in the U.S. District Court for the District of Columbia.

Manafort was Trump's campaign manager for five months in 2016. He was originally indicted last year with Gates, Trump's former deputy campaign manager.

Gates agreed to cooperate with Mueller as part of a plea deal to charges that he lied to investigators and conspired against the United States.

Gates' move was seen as adding to pressure on Manafort to cut a deal himself but he said in a statement issued last Friday after Gates' plea deal that he maintained his innocence.

(Reporting by Sarah N. Lynch; Editing by Leslie Adler and Susan Heavey)