US President Joe Biden’s son Hunter Biden has agreed to plead guilty on two federal tax charges and seek a separate agreement on a firearm charge in a deal with the Justice Department, according to his lawyer and court documents.

In a statement provided to several US news outlets, the younger Biden’s lawyer confirmed on Tuesday that “Hunter will take responsibility for two instances of misdemeanor failure to file tax payments when due pursuant to a plea agreement.”

The lawyer, Christopher Clark, added that a separate firearms charge, “will be subject to a pretrial diversion agreement and will not be the subject of the plea agreement”. A “pretrial diversion” is typically an agreement between defendants and prosecutors that allows rehabilitation instead of prison time.

The gun charge relates to Hunter Biden’s possession of a Colt Cobra 38 special handgun for 11 days in October 2018, despite knowing he was a drug user – a violation of federal law. The count carries a maximum sentence of up to 10 years in prison

“I know Hunter believes it is important to take responsibility for these mistakes he made during a period of turmoil and addiction in his life. He looks forward to continuing his recovery and moving forward,” the statement said.

Justice Department prosecutors also outlined the planned agreements in a court filing.

Any deal between Hunter Biden and prosecutors would have to be approved by a federal judge.

The deal is expected to end a yearslong federal probe into the younger Biden’s personal and professional dealings that has long presented a political headache for his father, while fuelling criticism – and conspiracy theory – from the right.

In a brief statement, White House spokesperson Ian Sams said: “The President and First Lady love their son and support him as he continues to rebuild his life. We will have no further comment.”

The wide-ranging federal investigation stretches back to at least 2018, and has probed the younger Biden’s ballooning foreign business deals after his father became vice president in 2008.

Meanwhile, Hunter Biden’s battles with addiction became increasingly public as his father geared up to run for president in the 2020 elections. He has said the struggles were compounded by the 2015 brain-cancer death of Joe Biden’s oldest son, Beau.

The president has not been implicated in any wrongdoings, but allegations against his son have long been seized on by his Republican political opponents as evidence of wider malfeasance. House Republicans are currently conducting a separate investigation into Hunter Biden.

In a tweet on Tuesday, Republican US Representative James Comer, who is leading the congressional investigation, said “Hunter Biden is getting away with a slap on the wrist”.

He said Republicans have uncovered growing evidence that “reveals the Bidens engaged in a pattern of corruption, influence peddling, and possibly bribery”.

Alleged efforts to pressure Ukraine to provide damaging information on Hunter Biden’s business interests in the country were the subject of former President Donald Trump’s first impeachment in the US House of Representatives. He was later acquitted in a Senate trial.

Posting on his Truth Social platform, Trump decried the reported deals a “mere traffic ticket”. The former president is currently facing both state and federal charges related in two separate cases, as well as several ongoing criminal investigations.

It is not clear when Hunter Biden might appear in the Delaware court where the agreements are to be filed, as he lives in California.