- The tax case is scheduled to go to trial in California in September.
- He has pleaded not guilty to the charges.
US prosecutors in Hunter Biden's tax evasion case have accused him of accepting money from a Romanian oligarch who sought to "influence US government agencies".
The accusation is part of a larger case against the president's son, who is charged with evading $1.4m (£1.1m) in taxes between 2016 and 2019 while spending millions on luxury cars, drugs and escorts.
Republicans have long accused Hunter Biden, 54, of "influence peddling", although Congressional probes have yet to uncover any wrongdoing.
The tax case is scheduled to go to trial in California in September. He has pleaded not guilty to the charges.
According to a court filing made on Wednesday in a Los Angeles federal court, the Romanian national hired Biden for legal work in 2015, at a time when his father was vice-president under then-President Barack Obama.
While the filing only identifies the Romanian businessman by his initials, GP, US media has identified him as Gabriel Popoviciu, who at the time was facing corruption charges in Romania.
In the filing, prosecutors said they plan to introduce evidence that Hunter Biden and an associate "received compensation from a foreign principal who was attempting to influence US policy and public opinion" and prompt the US "to investigate the Romanian investigation of GP".
The document also says that Biden and his associate "were concerned that lobbying work might cause political ramifications for the defendant's father" - Joe Biden - and wanted to conceal the "true nature" of the arrangement.
In total, prosecutors believe that Biden and two associates split $3m in payments from Popoviciu.
Popoviciu was sentenced to seven years in a Romanian prison on real estate fraud charges in 2017. He denied any wrongdoing.
Republicans in the House of Representatives - who last year opened an impeachment inquiry into the Biden family's foreign business ties - had previously raised concerns about ties between Hunter Biden and Popoviciu.
"Told ya," the House Judiciary Committee's Republican wing wrote in a brief post on X, formerly Twitter.
James Comer, the chair of the House Oversight Committee, tweeted "bank records don't lie".
The latest claims against Hunter Biden come less than two months after he was found guilty on all three charges in a federal gun trial held in Delaware.
While he faces a maximum of 25 years in prison, he is a first-time, non-violent offender and experts say it is highly unlikely he will receive such a lengthy sentence.