WASHINGTON • US President Donald Trump's former campaign chairman Paul Manafort has agreed to plead guilty to two criminal counts as part of a deal with Special Counsel Robert Mueller, court documents showed yesterday - in what could be a blow to Mr Trump in the investigation of Russian election influence.

As part of the deal, Manafort, 69, could be required to cooperate with Mr Mueller's probe into Russia's role in the 2016 presidential election and whether Mr Trump's campaign colluded with Russia in that election.

Manafort will plead guilty to one count of conspiracy against the United States and one count of conspiracy to obstruct justice, according to documents filed in the US District Court for the District of Columbia. Five other charges were dropped in the new court filing.