The US House of Representatives has voted to formalise its impeachment inquiry into President Joe Biden.
Lawmakers voted along party lines to back a resolution that Republicans say will give them more power to gather evidence and enforce legal demands.
Three Republican-led House committees allege bribery and corruption during Mr Biden's tenure as vice-president.
But they have yet to present evidence of wrongdoing, and Mr Biden says his opponents are "attacking me with lies".
The lower chamber of Congress, which Republicans control by a slim eight-seat margin, approved the inquiry on Wednesday afternoon by a vote of 221 to 212.
Voting to authorise an inquiry is not the same as voting for impeachment, but it advances the likelihood that the House will eventually seek to impeach Mr Biden.
In a statement, House Speaker Mike Johnson said the chamber "will not prejudge the investigation's outcome" but "the evidentiary record is impossible to ignore".
A formal impeachment investigation, that leads to a House vote and a Senate trial, could represent a major headache for the president in the midst of an election year.
But, even if the House ultimately opts to impeach the president, the Democrat-controlled Senate is all but certain to acquit him.
"The American people need their leaders in Congress to take action on important priorities for the nation and world," Mr Biden said in a statement following the vote.
"Instead of doing their job on the urgent work that needs to be done, they are choosing to waste time on this baseless political stunt that even Republicans in Congress admit is not supported by facts."
In an animated debate ahead of the vote, Oklahoma Republican Tom Cole said his colleagues had been left with no choice but to bring the measure.
He said it was a "sad day for myself, the institution and the American people" and accused the White House of "stonewalling" the impeachment inquiry.
But Democrats expressed irritation over what they have dismissed as "an extreme political stunt".
Jamie Raskin of Maryland said the investigation "isn't a whodunit, it's a what is it".
"It's like an Agatha Christie novel, where the mystery is - what's the crime?" he added.
Ex-Speaker Kevin McCarthy launched the inquiry in September and said Republicans had unearthed a "culture of corruption" surrounding Mr Biden.
Republicans have held one hearing related to the inquiry, during which two expert witnesses called by Republicans said there was not yet enough evidence to impeach the president.
The oversight committee claims the Biden family and its business associates received more than $24m (£19m) from foreign sources in China, Kazakhstan, Romania, Russia and Ukraine between 2014 and 2019.
Committee chairman James Comer has alleged that Mr Biden's relatives - in particular his son, Hunter - sold access to the then-vice-president and influence-peddled off "the Biden brand".
He has further alleged that the president "spoke, dined, and developed relationships with" his son's business partners.
Following Wednesday's vote, Mr Comer told reporters that unanimous Republican backing for the inquiry sent a "strong message" to the administration.
"We have a simple question that a majority of Americans have - what did the Biden family do to get millions?" he said.
Before and during his presidency, Mr Biden has said that he never talked business with Hunter Biden or his associates and that his son made no money off unethical overseas ventures.
The White House has also pushed back on the claim it is refusing to co-operate and criticised the inquiry on Wednesday as an abuse of power by House Republicans.
Hunter Biden has long been viewed by Republicans as the greatest political liability for his father.
If they are able to link his business dealings and personal conduct to the president, and perhaps even if they are not, it has the potential to damage the elder Mr Biden's standing with American voters.
As Mr Biden, 81, gears up for re-election, he is likely to face off against Donald Trump, 77, a twice-impeached former president and the current Republican frontrunner, in the November 2024 general election.
Mr Trump, who has vowed retribution against his political opponents, has urged his Capitol Hill allies to move quickly to impeach his successor.
