FBI Director James Comey is expected to officially undercut President Donald Trump's claims that he was wiretapped by the Obama administration during testimony before Congress on Monday, according to ABC News.

Citing people who are familiar with Comey's thinking, the FBI director will likely make US law enforcement's most public rebuke to date of Trump's allegations.

Comey is set to testify at a rare public hearing on Monday about alleged Russian meddling in the 2016 presidential election.

US lawmakers from both parties said on Sunday they had seen no proof to support the claim by Trump, adding pressure on the president to explain or back off his repeated assertion.

Several Republicans last week urged Trump to apologize 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.

FBI Director James Comey (above) is expected to be asked about President Donald Trump's claims that he was wiretapped by the Obama administration when he testifies at a rare public hearing on Monday about alleged Russian meddling in the 2016 presidential election

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

'I do believe he owes us that explanation.'

Collins said she supported Trump as president, but she wouldn't side with him if he 'misstated what the facts are.'

Representative Adam Schiff, the top Democrat on the House Intelligence Committee holding the hearing, called Trump's claims 'patently false' and said he expected Comey to say as much on Monday.

The two top lawmakers on the House Intelligence Committee - Chairman Devin Nunes (left), a Republican from California, and Adam Schiff (right), the top Democrat - said on Sunday they have seen no evidence to support Trump's claim that he was wiretapped by Obama

The Justice Department on Friday delivered documents to congressional committees to help clear up whether the Obama administration spied on Trump.

Russia has denied the assertion it was involved in hacked emails and other attempts to influence the race, but Schiff says the material offers circumstantial evidence that American citizens colluded with Russians in Moscow's efforts to interfere in the presidential election.

'There was circumstantial evidence of collusion; there is direct evidence, I think, of deception,' Schif said.

'There's certainly enough for us to conduct an investigation.'

Mike Rogers, the director of the National Security Agency, is also slated to testify along with Comey.

Intelligence officials have said that Russia was behind the theft of Democratic National Committee emails last summer.

Republican Senator Tom Cotton (above) also said Sunday they had seen no evidence that the Obama administration had placed Trump under surveillance at Trump Tower

The US government later concluded that the Russian government directed the DNC hack in an attempt to influence the outcome of November's presidential election.

'For the first time the American people, and all the political parties now, are paying attention to the threat that Russia poses,' committee Chairman Devin Nunes, a Republican from California, said.

'We know that the Russians were trying to get involved in our campaign, like they have for many decades. They're also trying to get involved in campaigns around the globe and over in Europe.'

Nunes said the committee will also examine whether the Russians were trying to sow doubt in the US electoral system or whether they were trying to help Trump get elected to the White House.

'We need to get to the bottom of that,' Nunes said.

Nunes and Schiff were among a number of lawmakers who said on Sunday's news shows they had seen no evidence that the Obama administration ordered wiretaps on Trump during the campaign.

'Was there a physical wiretap of Trump Tower? No, there never was,' Nunes said.

'The information we received Friday continues to lead us in that direction.'

Nunes added: 'There was no FISA warrant I am aware of to tap Trump Tower.'

FISA stands for the Foreign Intelligence Surveillance Act, which requires investigators to seek a warrant from a secret court to wiretap a foreign suspect.

Republican Senator Tom Cotton of Arkansas also said Sunday they had seen no evidence that the Obama administration had placed Trump under surveillance at Trump Tower, the Manhattan high-rise that houses Trump's residence, business office and campaign office.

The president repeatedly insisted last week that Obama had Trump Tower put under surveillance late last fall.

Trump's claims widened to two of the US's staunchest allies. He repeated an unsubstantiated claim that Britain's cyber intelligence organization conducted the surveillance at Obama's behest, a claim the agency GBHQ flatly denied; and mentioned during German Chancellor Angela Merkel's first visit to the Trump White House the Obama administration's monitoring of Merkel's cellphone, a bruising incident in German-US relations.

'What the president said was just patently false,' Schiff said of the Trump Tower allegations, 'and the wrecking ball it created has now banged into our British allies and our German allies and continuing to grow in terms of damage. And he needs to put an end to this.'

Nunes spoke on 'Fox News Sunday;' Schiff and Collins appeared on NBC's 'Meet the Press;' Cotton was on CNN's 'State of the Union.'