Donald Trump’s former campaign chairman Paul Manafort will cooperate with special counsel Robert Mueller as part of a guilty plea deal reached on Friday afternoon [local time].

Mr Manafort is the fifth person from the Trump campaign team to plead guilty to criminal charges that stemmed in part from Mr Mueller’s investigation into Russian interference in the 2016 presidential election.

As part of his guilty plea to several charges including conspiring to defraud the United States and conspiring to obstruct justice, Mr Manafort will fully cooperate with Mr Mueller’s investigation.

Mr Manafort’s attorney, Kevin Downing gave a brief statement outside the courthouse after the plea hearing.

“He wanted to make sure his family remained safe and live a good life,” Mr Downing said of the guilty plea. “He has accepted responsibility.”

When asked if the deal with Mr Mueller’s team is a full cooperation agreement, Downing replied “it is”.

Special counsel Robert Mueller appears to be zeroing in on the Trump administration. Photo: Getty

The 69-year-old was charged with tax fraud in Virginia last month for funnelling millions of dollars into offshore accounts earned from his work as a political lobbyist for former Ukrainian president Viktor Yanukovych.

According to The Washington Post, Mr Manafort used his influence in the United States to try to influence public opinion toward Mr Yanukovych – a pro-Russian politician – and Ukraine.

According to documents filed by prosecutors, Mr Manafort defrauded the United States of more than $US15 million ($20.9 million) in taxes.

Donald Trump tapped Mr Manafort, a former confidant to Ronald Reagan, to serve as his campaign chairman in June 2016 but he resigned in August amid increasing scrutiny over his ties to Ukraine.

Mr Manafort’s plea deal comes after Mr Trump’s longtime lawyer Michael Cohen also agreed to cooperate with the Mueller investigation last month, angering the president who called him a “flipper”.

White House press secretary Sarah Huckabee Sanders issued a brief statement following the announcement on Friday, distancing Mr Trump from the charges.

“This had absolutely nothing to do with the president or his victorious 2016 presidential campaign,” she said. “It is totally unrelated.”

Mr Manafort’s cooperation with Mr Mueller could provide new leads and evidence in their investigation into whether the Trump campaign colluded with the Russian government to influence the outcome of the election.

Ebony Bowden contributed reporting from New York City.