US President Joe Biden's son, Hunter, has pleaded not guilty to tax offences in a California federal court.

He was indicted last month on nine criminal counts, including for failing to pay his taxes on time from 2016 to 2019, filing false tax returns in 2018 and tax evasion.

If convicted on these charges, Mr Biden could face up to 17 years in prison.

He is also facing federal charges over felony gun offences, to which he has already pleaded not guilty.

Mr Biden, 53, made his first appearance in the tax case at a downtown Los Angeles courtroom on Thursday afternoon, where a sea of cameras had gathered outside and US Secret Service officers had earlier conducted a security sweep.

Bypassing the press through a rear entrance, he sat solemnly at the defence desk between his lawyers, then stood as his lawyer entered a not guilty plea on his behalf.

The father of four agreed to be released without detention on several conditions, including that he cannot drink, consume drugs, maintain employment or buy guns.

If he violates the terms of his release, the judge warned there would be an arrest warrant out for the president's son and he may be imprisoned.

The 30-minute arraignment was the latest development in a five-year investigation by federal prosecutors into Mr Biden's finances.

Over the summer, he appeared to be close to a plea deal that would see him admit wrongdoing on his tax offences, undergo drug treatment and monitoring for two years to resolve his gun offences, and avoid jail time.

But the agreement, which was heavily criticised by Republicans as a "sweetheart deal", collapsed under scrutiny from a judge.

As a result, Mr Biden was indicted in Delaware in September on three charges related to his illegal purchase of a firearm in 2018.

According to the 56-page charge sheet filed against Mr Biden in December over his tax charges, he made more than $7m (£5.5m) in gross income between 2016 and 2020 from business dealings in Ukraine, and related to connections from Romania and China.

Prosecutors say Mr Biden "wilfully" failed to either pay or file his taxes to the Internal Revenue Service from 2016 to 2019, instead spending his money on personal extravagances.

"Between 2016 and Oct 15, 2020, the defendant spent this money on drugs, escorts and girlfriends, luxury hotels and rental properties, exotic cars, clothing, and other items of a personal nature, in short, everything but his taxes," the document states.

Both the tax and gun charges span a period when Mr Biden was addicted to alcohol and crack cocaine.

In his memoir Beautiful Things, he wrote that he had abused substances to cope with the grief of losing his older brother Beau to brain cancer in 2015.

Since then, Mr Biden says he has become sober.

He has also paid off all his tax debts, including penalties and interest, largely with the help of loans from Kevin Morris, a close friend and LA-based entertainment attorney.

But Mr Biden's latest indictment presents a fresh challenge to his father, who is seeking re-election to the White House later this year.

The collapse of his plea deal has all but ensured Mr Biden will face a criminal trial while President Biden is on the 2024 campaign trail.

Congressional Republicans are also investigating the younger Biden's finances as part of their impeachment inquiry into the president.

They have alleged that Mr Biden and his relatives improperly profited off his father's "brand" during Joe Biden's vice-presidency. The inquiry has yet to provide evidence that directly implicates the president of wrongdoing.

On Wednesday, two Republican-led panels voted to recommend that Mr Biden be held in contempt of Congress for refusing to testify behind closed doors in their impeachment probe.

But the president's son and his lead defence lawyer, Abbe Lowell, threw the House oversight committee room into chaos when he showed up as the panel began debating the contempt resolution.

In an MSNBC interview broadcast on Thursday morning, First Lady Jill Biden said: "I think what they are doing to Hunter is cruel, and I'm really proud of how Hunter has rebuilt his life after addiction."