US Attorney General Merrick Garland announced on Friday that he would appoint a special counsel to investigate whether Hunter Biden, President Joe Biden's son, participated in improper business dealings.
Mr Garland said he would appoint David Weiss, the US prosecutor in Delaware who has already been investigating Hunter Biden's financial dealings, as the special counsel.
The announcement comes after some Republicans criticised the Justice Department for conducting two investigations into former president Donald Trump, but none into the younger Mr Biden.
Republicans in the House of Representatives have also considered the possibility of launching an impeachment inquiry into President Biden over allegations that the elder Mr Biden benefited from his son's business dealings.
“The appointment of Mr Weiss reinforces for the American people the department's commitment to both independence and accountability in particularly sensitive matters,” Mr Garland said.
He added that Mr Weiss had told him that, “in his judgment, his investigation has reached a stage at which he should continue his work as a special counsel, and he asked to be appointed”.
“Upon considering his request, as well as the extraordinary circumstances relating to this matter, I have concluded it is in the public interest to appoint him as special counsel,” Mr Garland said.
As special counsel, Mr Weiss will be able to conduct his investigation with more freedom than federal prosecutors typically have. He was first appointed by Mr Trump but was allowed to stay during the Biden administration.
Mr Weiss previously charged Hunter Biden for failing to pay taxes in 2017 and 2018, as well as unlawful possession of a firearm.
A federal judge last month rejected a plea deal from Hunter Biden in which he would have pleaded guilty to the tax charge but avoided the gun charge.