US President Joe Biden's son Hunter Biden has been criminally charged with deceiving a gun dealer into selling him a firearm, in the first-ever prosecution of a sitting president's child.
The indictment filed on Thursday in US District Court in Delaware charged Hunter Biden with three criminal counts related to lying about the fact that he was using illegal drugs at that time, which would have banned him under the law from owning a firearm.
The charges ensure that courtroom drama will play an outsized role in the 2024 US presidential campaign as Joe Biden, 80, seeks re-election in a likely rematch with his Republican predecessor Donald Trump, 77, who faces four upcoming criminal trials.
The new charges against Hunter Biden brought by recently elevated US Special Counsel David Weiss say nothing about any violations of US tax law.
A prior deal under which Hunter Biden, 53, would have pleaded guilty to two misdemeanor tax charges and enroll in a program to avoid prosecution on a gun-related charge collapsed in a stunning turn in a July hearing.
Prosecutors accused the younger Biden of lying about his use of narcotics when he purchased a Colt Cobra handgun in October 2018.
It comes two days after House of Representatives Republicans moved to open an impeachment inquiry of Joe Biden related to Hunter Biden's foreign business dealings.
A lawyer for Hunter Biden could not be immediately reached for comment.
Weiss was elevated to special counsel status in August after investigating Hunter Biden's business dealings for years as the US attorney in the Democratic president's home state of Delaware.
Weiss was originally nominated by Trump.
The younger Biden for years has been the focus of unrelenting attacks by Trump and his Republican allies who have accused him of wrongdoing relating to Ukraine and China, among other matters.
Hunter Biden has worked as a lobbyist, lawyer, investment banker and artist, and has publicly detailed his struggles with substance abuse.
While Republican lawmakers have collected testimony that Joe Biden at times joined calls with his son's business associates, they have yet to produce evidence that the president personally benefited.
Hunter Biden disclosed in December 2020 that Weiss's office was investigating his tax affairs.
He has denied wrongdoing.
While most US attorneys appointed by Trump were asked to step down when Biden took office in January 2021, as is routine, the Justice Department asked Weiss to stay on.
The US Justice Department's inquiry has itself come under scrutiny from Republicans after whistle-blowers from the Internal Revenue Service assigned to the investigation told Congress that the department slow-walked the probe and limited Weiss' ability to bring charges.
Weiss has denied the claims.
Hunter Biden never held a position in the White House or on his father's campaign.
The president has said he has not discussed foreign business dealings with his son and has said his Justice Department would have independence in any investigation of a member of his family.
Trump and other Republicans have alleged what they called conflicts of interest from Hunter Biden's position on the board of the Ukrainian energy company Burisma at the time his father was vice president to Democratic President Barack Obama.
Hunter Biden described in a 2021 memoir dealing with substance abuse issues in his life including crack cocaine use and alcoholism.
He was discharged from the US navy reserve in 2014 after, sources said at the time, testing positive for cocaine.
Hunter Biden initially agreed to plead guilty to charges that he failed to pay more than $US100,000 ($A155,400) in income taxes in 2017 and 2018.
The deal collapsed after a federal judge questioned whether the agreement would bar prosecutors from bringing charges on other issues.
Hunter Biden appears to be the first child of a sitting president to be indicted, according to Aaron Crawford, who specialises in presidential history at the University of Tennessee.