The Republican-controlled US House of Representatives voted on Wednesday night to authorise a formal impeachment inquiry into President Joe Biden over his son's business dealings.
The chamber voted 221-212 along party lines to approve the investigation.
Republicans have alleged that Hunter Biden improperly benefited from decisions the elder Mr Biden participated in while he was vice president from 2009 to 2017.
The investigation has yet to reveal any evidence of wrongdoing by the President.
While it is unlikely any proceedings will result in Mr Biden being removed from office – the President's Democratic Party control the chamber by a slim margin – it could help Republicans highlight their allegations of corruption during the 2024 campaign.
Following the announcement, the President said that Republicans in the House were focused on attacking him "with lies" and called the inquiry a "baseless political stunt".
The younger Mr Biden criticised the investigation into his father in a media briefing at Capitol Hill on Wednesday morning.
He said he would not co-operate with a subpoena that compelled him to provide testimony behind closed doors.
“There is no evidence to support the allegations that my father was financially involved in my business, because it did not happen,” Hunter Biden said.
Republicans on the House oversight committee said they could hold the younger Biden in contempt.
“The President's son does not get to set the rules,” panel chairman James Comer said.
House Democrats on the committee said they understood Mr Biden's decision not to testify.
“They [Republicans] continued to cherry pick little pieces of evidence and distort and misrepresent what has taken place,” said Jamie Raskin.
The White House said Mr Biden was aware of what his son had planned on saying outside the Capitol.
The White House press secretary said the President and his wife were proud of their son.
The White House has also dismissed the impeachment inquiry and claims it is politically motivated against Mr Biden before the 2024 presidential election, where he is expected to face twice-impeached president Donald Trump.
Hunter Biden, who has described his struggles with drug and alcohol addiction, has also been subject of a years-long criminal investigation.
“In the depths of my addiction, I was extremely irresponsible with my finances,” he said. “But to suggest that is grounds for an impeachment inquiry is beyond the absurd. It's shameless.”
While his father was vice president, Hunter Biden served on the boards of a Ukrainian industrial conglomerate and a Chinese private equity fund.
One of his former associations has testified that he sought to provide an “illusion of access” to his father, although he said he was not aware of any wrongdoing by the elder Mr Biden.
He has offered to testify in public, which would give him a chance to defend his record and his father in what would probably be a high-profile televised election-year showdown.
Hunter Biden said he was concerned that testimony behind closed doors would be misrepresented.
