The head of a US congressional panel investigating allegations of Russian interference with the nation’s election says there is no evidence of such accusations. 

Lawmakers from both parties who sit on the panel also reported there was no evidence to support President Donald Trump’s claims that Barack Obama wiretapped him during and lead up to the election. 

Republican Devin Nunes, chairman of the house intelligence committee, told Fox News that leaks involving Mr Trump’s former aide Michael Flynn were criminal and his panel would investigate whether other names were leaked.

“The one crime we know that’s been committed is that one: the leaking of someone’s name,” Mr Nunes, chairman of the House of Representatives Permanent Select Committee on Intelligence, told Fox News on Sunday.

The White House and Mr Trump’s allies have sought to focus attention away from wiretapping claims by calling for investigations of leaks to the news media.

Mr Nunes said the leak was the only crime the panel had seen so far, with no evidence to support the President’s claims of Barack Obama-led wiretapping during the 2016 election, increasing pressure for Mr Trump to explain or back off his repeated assertion.

Mr Trump had also been dogged by allegations that his associates had ties to Russian officials. The US President fired Mr Flynn, his former national security adviser, last month after he failed to disclose contacts with Russia’s ambassador before Mr Trump took office.

Mr Trump has found himself at odds with Democrats and Republicans alike, including Mr Nunes, over his March 4 assertion that the Obama administration tapped his phones during the 2016 presidential campaign.

Mr Nunes, along with House of Representatives speaker Paul Ryan and other leading Republicans have said no such wiretap took place.

Today Mr Nunes and Adam Schiff, the top Democrat on the House intelligence committee, will lead a rare open hearing on the investigation into Russian election meddling where the directors of the Federal Bureau of Investigation and National Security Agency are expected to testify.

The Russian government has rejected an accusation by US intelligence agencies that it worked to influence the election in Mr Trump’s favour by hacking computer systems, among other methods.

Mr Trump won’t apologise for his wiretapping allegations. Photo: Getty

While disagreeing with Mr Trump’s wiretap assertions, Mr Nunes agreed with concerns that the Republican president had expressed about alleged leaks in the probe.

The panel will now investigate whether names other than Mr Flynn’s were leaked to the media.

Several Republicans last week urged Mr Trump to apologise for the allegations he made in a series of tweets on March 4. The maelstrom also caused tension with key US allies and threatens to distract Republicans from campaign promises on health care and taxes.

“I don’t know the basis for President Trump’s assertion,” US Senator Susan Collins, a Republican, said on NBC’s Meet the Press on Sunday.

“I do believe he owes us that explanation.”

Ms Collins said she supported Mr Trump’s presidency, but she would not side with him if he “misstated what the facts are”.

FBI Director James Comey is expected to be asked about Mr Trump’s claims when he testifies the public hearing.

– with AAP.