Paul Manafort pleads not guilty over money laundering conspiracy charges

US president Donald Trump's former campaign chairman Paul Manafort has maintained his innocence over new charges that he acted as an unregistered foreign agent and directed an international money laundering conspiracy.

Manafort appeared at a federal courthouse and entered a formal plea of not guilty to a second indictment brought against him by prosecutors working for special counsel Robert Mueller, who is investigating Russian election interference.