US President Joe Biden's son Hunter was indicted Thursday for illegally buying a gun five years ago at a time when he admits he was using drugs heavily.

Hunter Biden was charged with two counts of making false statements, for claiming on forms that he was not using drugs illegally at the time he bought a Colt revolver in Delaware.

A third charge said that, based on the false statements, he illegally possessed the gun -- a charge that can bring up to 10 years in prison.

The charges were filed by Justice Department Special Counsel David Weiss, who has been investigating Biden since 2018.

It came two months after a plea deal between Biden and Weiss, covering the gun charge as well as alleged tax violations, went sour over differences of whether the president's son could face unspecified additional charges.

In the July deal, Biden agreed to plea guilty to two minor tax charges.

In exchange he was offered probation, as he had already paid what he owed the government along with penalties.

In the same deal, Weiss agreed to suspend the felony gun charge if Biden completed "pretrial diversion," which often involves counseling or rehabilitation.

But in a dramatic July 26 hearing, the deal collapsed over the issue of whether Biden would have been immune from any other charges also investigated by Weiss, including possible crimes related to his business dealings in Ukraine, China and elsewhere.

The judge mentioned the possibility that Biden could be charged as having acted as a lobbyist for foreign governments without registering with the Justice Department.

Three weeks later, after the deal collapsed, Weiss dropped the tax charges and indicated in a court filing that new charges would be brought in other states.

And he told the Deleware court that an indictment on the gun charge would come by the end of September.

The legal troubles of Biden, 53, a Yale-trained lawyer and lobbyist, have cast a shadow over his father's reelection campaign.

Without offering any evidence, Republicans have accused Biden's Justice Department of protecting his son and have accused Weiss, a Republican appointee, of going easy on Hunter.