Senior Republican Kevin McCarthy has announced a formal impeachment inquiry against President Joe Biden claiming they have unearthed a "culture of corruption" surrounding the president.
The inquiry will focus on accusations of improper business dealings on the part of the president's son, Hunter Biden, and on whether the president benefited from his son's business dealings.
Here's what we know about the specific claims that the inquiry is likely to focus on.
Alleged payments to Biden Family
In a memorandum released in early August, the House Oversight Committee claimed that evidence suggested that the Biden family and their business associates had received more than $20m (£16m) in payments from foreign sources in countries including China, Kazakhstan, Ukraine, Russia and Romania.
The committee's chairman, Kentucky Republican James Comer, has said - without substantial evidence - that Hunter Biden "sold" his father - then Barack Obama's vice-president - as a "brand" to "reap millions from oligarchs".
But in a 9 August statement, Mr Comer said that "it appears no real services were provided other than access to the Biden network, including Joe Biden himself". He also said that the elder Mr Biden dined at a fashionable Washington DC restaurant "with oligarchs from around the world who had sent money to his son".
An analysis of the evidence published by the Washington Post in August found that only $7m went to Biden family members - mostly Hunter - while the rest went to "associates". Mr Comer and other Republican lawmakers had suggested that the entire sum of $20m went to the Biden family.
Joe Biden as 'the brand'
Devon Archer, a former business partner of Hunter Biden, has said that the elder Mr Biden was put on speaker phone with potential business associates - including foreign nationals - "maybe 20 times" over the span of 10 years.
House Republicans have said the calls contradict Joe Biden's claims that he had never discussed business deals with his son.
Mr Archer testified that the phone calls were "casual conversations" that never delved into Hunter Biden's business dealings, and "never once spoke about any business dealings".
A report from the Congressional Integrity Project, a Democrat-aligned watchdog group, has said that Mr Archer's testimony "failed to produce a shred of evidence" of any conflict of interest of Mr Biden working on behalf of his son's business ventures.
Alleged bribery scheme
Republicans have also focused on an unverified tip to the FBI that said Joe Biden pressured Ukraine's government to fire a top prominent prosecutor to halt an investigation into Ukrainian energy firm Burisma, where Hunter Biden was on the board. The claim first emerged in 2019, during then-President Donald Trump's first impeachment.
An FBI document detailing the claim was obtained and released by Republican Senator Chuck Grassley in July. According to the document, former Burisma CEO Mykola Zlochevsky reportedly said that he paid $5m to both Joe and Hunter Biden.
The justice department investigated the claim for eight months during the Trump administration, but ultimately abandoned its probe due to "insufficient evidence".
Mr Zlochevsky later rebutted the claim and said that he had had no contact with Joe Biden or any of his staff members and that Mr Biden had never helped him or the company while serving as vice-president, according to a transcript of an interview released by Democratic Representative Jamie Raskin.
In his testimony, Mr Archer also said that he was unaware of any such payments.
Preferential treatment of Hunter Biden
Citing testimony from two Internal Revenue Service (IRS) whistleblowers, House Republicans have also suggested that the justice department intentionally interfered in a multi-year investigation into Hunter Biden's tax return.
In testimony given earlier this year, the two IRS agents said the justice department was "slow-walking" and blocking investigative steps.
House Republicans have said that the testimony is evidence that the justice department worked on behalf of Mr Biden to prosecute Donald Trump, while at the same time being lenient when looking into allegations against the president's son.
The department has denied the claims. Other witnesses called by Republican representatives in July testified that neither President Biden nor Attorney General Merrick Garland interfered in the investigation.
'Collusion' on Burisma inquiries
During his announcement of the impeachment inquiry, Mr McCarthy also referenced alleged communications between Joe Biden's staff members and Hunter Biden's team.
While Mr McCarthy offered no specifics, the reference is similar to claims made by the House Oversight Committee that the Office of the Vice President and a business associate of Hunter Biden "colluded" to co-ordinate responses to media questions regarding corruption at Burisma.
The committee cited a December 2015 email from Eric Schwerin, a Biden family business associate, to Office of the Vice President staff member Kate Bedingfield in which he provided "quotes the White House should use in response to media outreach regarding Hunter Biden's role in Burisma".
According to the committee, Ms Bedingfield responded saying that Vice-President Biden "signed off on this".
White House spokesman Ian Sams said the Burisma allegations were part of a "months-long effort to waste time and taxpayer resources on an evidence-free wild goose chase".