WASHINGTON (REUTERS) - United States President Donald Trump's former personal lawyer Michael Cohen pleaded guilty in New York on Tuesday (Aug 21) to campaign finance violations and other charges, saying he made payments to influence the 2016 election at the direction of a candidate for federal office.

Cohen, 51, appearing in federal court in Manhattan, pleaded guilty to one count of wilfully causing an unlawful corporate campaign contribution and one count of making an excessive campaign contribution.

He said he arranged to make payments "for (the) principal purpose of influencing (the) election" at the direction of a candidate for federal office.

He did not give the candidate's name.

Cohen, who agreed to a plea bargain with federal prosecutors earlier in the day, also pleaded guilty to five counts of tax fraud and one count of making false statements to a financial institution.

The deal includes a possible prison sentence of up to five years and three months, Judge William Pauley III said during the hearing. Judge Pauley scheduled sentencing for Dec 12 and set bail at US$500,000 (S$680,000).

The guilty pleas came in the same hour that a federal jury in Alexandria, Virginia, convicted former Trump campaign chairman Paul Manafort of eight charges of tax and bank fraud and failing to disclose foreign bank accounts.

The Manafort conviction resulted from US Special Counsel Robert Mueller's investigation into Russian meddling in the 2016 election and possible coordination with the Trump campaign.

The probe also led to a referral from Mr Mueller about Cohen to federal prosecutors in New York, who began their own probe of the longtime Trump lawyer.

Mr Trump has repeatedly denied any collusion and has called the Mueller investigation a witch hunt.

Russia has denied meddling in the election but US intelligence agencies have concluded that Moscow interfered.

Cohen was one of Mr Trump's closest associates for more than a decade. He worked as his personal attorney at the Trump Organisation and continued to advise the President after the election. But their relationship had frayed in recent months.

In court on Tuesday, Cohen's voice cracked as he answered questions from Judge Pauley.

Asked a standard question about whether he had consumed any alcohol or drugs before making his guilty plea, Cohen said he had taken only a glass of 12-year-old Glenlivet, single-malt scotch with dinner the night before.