PROSECUTORS in the trial of former Trump campaign chairman Paul Manafort say they intend to put his former deputy Rick Gates on the stand.

Gates is Manafort’s business associate. He pleaded guilty earlier this year and agreed to cooperate and special counsel Robert Mueller’s investigation. He has been regarded as the government’s star witness, and defense lawyers have already signaled that they plan to attack his credibility.

Prosecutors on Thursday said that they do intend to call Mr Gates as a witness after having suggested a day earlier that they had not made a final decision.

It comes as prosecutors claimed they will also ask jurors to follow the money in the Manafort trial, a trail they say shows that the former Trump campaign chairman took millions from wealthy Ukrainian clients then hid it from banks and the IRS.

Expected to testify were bookkeepers and accountants. The witness list appeared to be part of a broader strategy by prosecutors to directly link Mr Manafort to the financial fraud that government lawyers say enabled his extravagant lifestyle.

On Wednesday, lawyers relayed evidence they said showed Mr Manafort personally directed millions of dollars in international wire transfers to pay for high-end suits and more than $US3 million (A$4 million) in improvements at various houses.

Mr Manafort’s lawyers have signalled they will pin blame for any illegal conduct on his longtime deputy, Rick Gates. The trial is the first to stem from the Russia probe by special counsel Robert Mueller, who was tasked last year with investigating the Kremlin’s efforts to sway the US presidential election and potential collusion with the Trump campaign. That investigation remains ongoing, and this week’s financial fraud trial is not tied to collusion.

Still, the case has exposed the aggressive lobbying effort by foreign officials looking to influence US politics and pulled back the curtain on the man who steered Mr Trump’s election efforts for a time, including descriptions of Mr Manafort’s $US15,000 (A$20,000) jacket made of ostrich leather and the more than $US6 million (A$8 million) in cash he put toward real estate. One witness, Maximillian Katzman, testified that Mr Manafort spent more than $US900,000 (A$1.2 million) at his boutique retailer in New York. He said Mr Manafort was the only business client of his who paid via international wire transfer.

The prosecution’s focus on Mr Manafort’s personal finances — laid out in painstaking detail — at times tested the patience of US District Judge TS Ellis III. It’s not a crime to be wealthy, he noted. And using the pejorative term “oligarchs” and showing evidence of home renovations aren’t necessarily relevant to the charges in question, he added.

“The government doesn’t want to prosecute somebody because they wear nice clothes, do they?” Mr Ellis said. “Let’s move on.” Prosecutor Greg Andres argued that documenting Manafort’s spending for the jury was important to the case.

“Judge, this is not an effort to prove Mr Manafort lived lavishly,” Mr Andres said. “It’s evidence of his income.”

An FBI agent on Wednesday described the July 2017 raid on Mr Manafort’s Virginia condominium, saying he knocked multiple times before entering with a key and finding Mr Manafort inside. The searches described by agent Matthew Mikuska found expensively tailored suits and documents related to other luxury items allegedly bought by Mr Manafort, including two silk rugs bought for $US160,000 (A$215,000) paid from offshore accounts.

The proceedings clearly caught the attention of President Donald Trump, who defended his 2016 hiring of Mr Manafort and suggested his former campaign manager was being treated worse than mobster Al Capone.

White House press secretary Sarah Huckabee Sanders said the president indeed felt Manafort had been treated unfairly. “Why didn’t government tell me that he was under investigation,” Mr Trump tweeted on Wednesday. “These old charges have nothing to do with Collusion — a Hoax!”

Mr Manafort’s lawyers are putting the blame on Mr Gates, Mr Manafort’s business associate.

Mr Gates was expected to be the government’s star witness at trial, but prosecutor Uzo Asonye said he could not say with certainty whether Mr Gates would or would not testify. He later clarified to say that that uncertainty applies to any witness, not just Mr Gates, as the prosecution team assesses the pace of the trial and the evidence it needs.

Manafort has a second trial scheduled for September in the District of Columbia that would address allegations that he acted as an unregistered foreign agent for Ukrainian interests and made false statements to the US government. Mr Asonye also told Mr Ellis that prosecutors expect to rest their case next week, noting that they are “ahead of schedule.”