The US House of Representatives will open a formal impeachment inquiry into President Joe Biden, its most senior Republican has said.

Kevin McCarthy said the inquiry would focus on "allegations of abuse of power, obstruction and corruption" by Mr Biden.

Republicans have been investigating the president since they took control of the House in January.

The hearings have found no concrete evidence of misconduct by Mr Biden.

They have, however, shed more light on business dealings by the president's only surviving son Hunter Biden, which Republicans say are questionable - and on Mr Biden's knowledge of his son's activities.

In a brief statement at the US Capitol, Mr McCarthy said there were "serious and credible" allegations involving the president's conduct.

"Taken together, these allegations paint a picture of a culture of corruption," he said.

The White House was quick to condemn to Mr McCarthy's decision.

"House Republicans have been investigating the President for nine months, and they've turned up no evidence of wrongdoing," White House spokesperson Ian Sams wrote in a social media post.

"Extreme politics at its worst."

Hunter Biden is currently under federal investigation for possible tax crimes related to his foreign business interests.

Mr McCarthy also alleged that the president's family has received special treatment from Biden administration officials investigating allegations of misconduct.

Tuesday's announcement is the first move in a political process that could result in an impeachment vote in the House of Representatives.

If that is approved by a simple majority, a trial in the US Senate could follow.

This formal inquiry will give congressional investigators greater legal authority to investigate the president, including by issuing subpoenas for documents and testimony that can be more easily enforced in court.

Mr McCarthy, who leads Republicans in the House of Representatives, has been under pressure for weeks from right-wing members to open an impeachment inquiry.

Congressman Matt Gaetz of Florida, a close ally of former president Donald Trump, was reportedly planning to make remarks at the Capitol on Tuesday where he would threaten to force a vote on whether to remove Mr McCarthy if an impeachment inquiry were not initiated.

Mr McCarthy is currently trying to shepherd a series of spending bills through the House of Representatives - measures that must be approved by Congress by the end of September in order to avoid a partial shutdown of the US government.

The Republican majority in the House is exceedingly narrow, however, which means he can only afford to lose a handful of votes in the face of unified Democratic resistance.

Mr McCarthy's move to back impeachment could be viewed as an attempt to curry the favour of right-wing House Republicans in the lead-up to the budget battles to come.

Such a strategy comes with risks, however. Centrist Republicans in competitive districts have expressed unease with an aggressive impeachment push, worried that it will alienate the independent and moderate voters who carried them to victory - and delivered the House majority to their party.

Already Democrats are pointing out that Mr McCarthy sharply criticised Democratic leader Nancy Pelosi in 2019, when she announced an impeachment inquiry into Mr Trump without holding a formal vote.

She would take that step just over a month later.

While Mr McCarthy has only said he is approving an impeachment inquiry at this point, pressure will build for a formal authorising vote in the House to set the rules for impeachment hearings.

Such a vote would put those centrists on the record - and provide grist for Democratic attacks during the November 2024 general election.

That is a next-year problem for Mr McCarthy, however. For the moment, he is trying to keep unruly conservative members of Congress from openly rebelling - and forcing a vote on whether to remove him from his leadership job.

Impeachment - or at least a movement toward it - could buy him the political breathing room to survive the coming months.