Chairman of the US House of Representatives’ Intelligence Committee Devin Nunes says he is temporarily stepping down as head of the panel’s investigation into alleged Russian election tampering.

Mr Nunes cited what he described as “entirely false” accusations filed against him with the Office of Congressional Ethics.

The disclosure that Mr Nunes was under investigation added new uncertainty to his committee’s wider Russian probe.

Democrats claim Mr Nunes, a close ally of President Donald Trump, was too close to the White House and could not lead an impartial inquiry.

The investigation is examining whether Russia tried to influence the 2016 presidential election in Mr Trump’s favour, including through hacking Democratic operatives’ emails and releasing embarrassing information. Russia denies the allegations.

“Several left-wing activist groups have filed accusations against me with the Office of Congressional Ethics,” Mr Nunes said in a statement.

“The charges are … being levelled just as the American people are beginning to learn the truth about the improper unmasking of the identities of US citizens and other abuses of power.”

The House Ethics Committee issued a rare statement saying it would investigate allegations Mr Nunes may have made unauthorised disclosures of classified information “in violation of House Rules, law, regulations, or other standards of conduct”.

Mr Nunes has insisted no classified information was revealed.

However, Mr Nunes at one point during a March 22 news conference said that what he was discussing was “all classified information”.

Mr Trump sparked controversy in early March when he tweeted, without offering evidence, that Mr Obama had wiretapped him during the 2016 presidential race.

Later that month, Mr Nunes held a news conference saying an unidentified source had shown him intelligence reports containing “unmasked” names of Trump associates who were incidentally caught up in routine foreign surveillance.

Immediately after Mr Nunes’ news conference, critics argued that he had disclosed classified information in what many saw as an effort to provide cover to Mr Trump’s wiretapping claim and to distract from the wider Russia investigation.

Mr Nunes said the surveillance of Trump associates appeared legal but expressed concern that names of US citizens may have been improperly revealed in the reports and widely disseminated among government officials.

Support for Nunes’ decision

House Speaker Paul Ryan said he supported Mr Nunes’ decision\, adding that Republiocan congressman was eager to talk to the ethics panel.

“It is clear that this process would be a distraction for the House Intelligence Committee’s investigation into Russian interference in our election,” Mr Ryan said.

He said he believed it was in the best interests of the committee and Congress to place Republican Mike Conaway temporarily take charge of the investigation while the House Ethics Committee looked into the issue.

Michael Flynn’s resignation from national security post has the potential to threaten careers all the way to the top.

“I will continue to fulfil all my other responsibilities as committee chairman,” Mr Nunes said.

The top Democrat on the panel, Adam Schiff, said Mr Nunes’ decision to step aside from the probe was made in “the best interests of the committee, and I respect that decision”.

– With news agencies