WASHINGTON — A Russian billionaire close to President Vladimir Putin said Tuesday he is willing to take part in US congressional hearings to discuss his past business relationship with President Trump’s former campaign chairman, Paul Manafort.

In 2005, Manafort had written aluminum magnate Oleg Deripaska, proposing to do work for Deripaska that would ‘‘benefit the Putin government,’’ according to people familiar with Deripaska’s business dealings and documents.

In a quarter-page advertisement in Tuesday’s editions of The Washington Post and The Wall Street Journal, Deripaska said that he was ‘‘ready to take part in any hearings conducted in the US Congress on this subject in order to defend my reputation and name.’’

Manafort signed a $10 million contract in 2006 that laid out a four-country communications and political strategy intended to support Deripaska’s company and undermine anti-Russian political movements. Payments continued until at least 2009, seven years before Manafort joined and led Trump’s 2016 campaign, according to people familiar with the relationship. They spoke on condition of anonymity because they were not authorized to discuss the business arrangement openly.

In his newspaper ads responding to previous reports, Deripaska said he never signed ‘‘a $10 million contract ‘to greatly benefit the Putin government’ with Paul Manafort.’’

‘‘I have never made any commitments or contracts with the obligation or purpose to covertly promote or advance ‘Putin’s government’ interests anywhere in the world,’’ Deripaska wrote.

The Associated Press reported Manafort wrote a strategy memo proposing that the work he would do for Deripaska would ‘‘benefit the Putin government,’’ not that the contract contained that language.

The revelations about Manafort come as Trump campaign advisers are the subject of an FBI probe and two congressional investigations.