WASHINGTON • A former top adviser to Mr Donald Trump's presidential campaign has agreed to cooperate with the special counsel inquiry into Russia's interference in the 2016 election after pleading guilty to financial fraud and lying to investigators.

The adviser, Rick Gates, is a long-time political consultant who once served as Mr Trump's deputy campaign chairman.

The plea deal could be a significant development in the investigation - a sign that Gates plans to offer incriminating information against his long-time associate and the former Trump campaign chairman, Paul Manafort, and possibly other members of the campaign in exchange for a lighter punishment. He faces up to nearly six years in prison.

The deal came as the special counsel, Mr Robert Mueller, has been raising pressure on Gates and Manafort with dozens of new charges of money laundering and bank fraud unsealed on Thursday. Both men were first indicted last October and pleaded not guilty.

Gates changed his plea on Friday during an appearance in a Washington courtroom. The man who had made millions of dollars lobbying in Ukraine accepted the fate that may await him: a prison sentence for carrying out a financial conspiracy to hide the money he earned there.

He also admitted that he lied to investigators this month - while under indictment and negotiating with prosecutors - about the details of a 2013 meeting about Ukraine that Manafort had with a pro-Russian member of Congress.

What the courtroom scene might mean for Mr Trump depends on what Gates has to offer the special counsel, though at the least, the plea agreement is further evidence that the Trump campaign attracted a cast of advisers who overstepped legal and ethical boundaries.

A new indictment filed on Friday by Mr Mueller also alleged that Manafort secretly paid a group of former senior European politicians more than €2 million (S$3.2 million) in 2012 and 2013 to lobby for the pro-Russia government of Ukraine.

NYTIMES, REUTERS