WASHINGTON — Paul Manafort, President Trump’s former campaign chairman and one of Washington’s most prominent lobbyists, is close to a plea deal with federal prosecutors to avoid a trial scheduled for next week on charges stemming from work he did for pro-Russia political forces in Ukraine, people familiar with the case said on Thursday.

Mr. Manafort has already been convicted on related bank and tax fraud charges arising from an investigation by the special counsel, Robert S. Mueller III. The negotiations over a plea deal relate to a separate set of seven charges encompassing conspiracy, obstruction of justice, money laundering, false statements and violations of a lobbying disclosure law.

It was not clear which charges Mr. Manafort might plead guilty to or whether he would cooperate with Mr. Mueller’s team in its investigation into Russian interference in the 2016 election, possible collusion with the Trump campaign and obstruction of justice by Mr. Trump. The developments in plea negotiations were first reported by ABC News.

Mr. Manafort’s trial on the second set of charges is scheduled to get underway on Monday in United States District Court in Washington. A pretrial hearing, which had been postponed this week, is scheduled for Friday.