Updated 17:20

US senators have begun examining an FBI report on Donald Trump's Supreme Court nominee Brett Kavanaugh, with Democrats and Republicans offering different responses to the findings.

A key Republican suggested the investigation appeared to be 'very thorough', while Democrats raised concerns about the scope of the investigations.

The FBI 'supplemental background check' was requested following the allegations of sexual misconduct against Judge Kavanaugh.

Following the public testimony of accuser Christine Blasey Ford last week, Republican Senator Jeff Flake dramatically announced he would not support the confirmation of Judge Kavanaugh unless an FBI investigation was carried out into the allegations.

Republicans agreed to a week-long delay on a confirmation vote to allow for the investigation, and that investigation has now been completed.

Overnight, the White House said it had received the additional FBI information.

Spokesperson Raj Shah said "the White House is fully confident the Senate will vote to confirm Judge Kavanaugh to the Supreme Court".

With Leader McConnell’s cloture filing, Senators have been given ample time to review this seventh background investigation. This is the last addition to the most comprehensive review of a Supreme Court nominee in history, which includes extensive hearings, multiple (2/3)

— Raj Shah (@RajShah45) October 4, 2018

Ahead of a planned procedural vote on the nomination tomorrow, Republicans and Democrats have alternating access to the report for one-hour stretches today.

Chuck Grassley - the head of the Senate Judiciary Committee, which has been holding the Kavanaugh hearings - confirmed the report had been received in the early hours of the morning.

While the contents of the confidential report will not be publicly released, Senator Grassley today claimed: "There’s nothing in it that we didn’t already know." 

In comments quoted by US media, he said: "These uncorroborated accusations have been unequivocally and repeatedly rejected by Judge Kavanaugh, and neither the Judiciary Committee nor the FBI could locate any third parties who can attest to any of the allegations."

More significantly, two key Republican senators - Jeff Flake and Susan Collins, seen as possible 'swing votes' in the confirmation process - appeared to express satisfaction with the report.

Susan Collins. Picture by: Alex Brandon/AP/Press Association Images

Along with their colleague Lisa Murkowski, the support of the two senators is seen as critical to Kavanaugh's confirmation - if two Republican senators vote against their party colleagues, the nomination is likely to be rejected.

Today, Senator Collins said the investigation appeared to be 'very thorough', although added she would return later to read the full interviews.

Senator Flake indicated they had seen "no additional corroborating information" in the report, The Washington Post reported.

Scope of investigation

Democrats, however, offered a different reaction to the report after their first hour examining the findings.

Diane Feinstein - the ranking Democrat on the judiciary committee - told reporters: "The most notable part of this report is what's not in it.

"We have seen even more press reports of witnesses who wanted to speak with the FBI, but were not interviewed."

Concerns had been raised about the scope of the investigation ahead of the report's completion, with US media reporting that many of those who claimed to have information had not been contacted by the FBI.

Agents did contact Deborah Ramirez - the second woman to have accused the nominee of sexual misconduct.

However, Dr Ford and Judge Kavanaugh themselves weren't interviewed as part of the investigation.

Senator Grassley suggested: "Dr Ford & Judge Kavanaugh had opportunity to testify under oath [before] public/[committee] to tell senators what they know."

In a statement quoted by The Washington Post, meanwhile, Dr Ford's lawyers said: "An FBI supplemental background investigation that did not include an interview of Dr Christine Blasey Ford - nor the witnesses who corroborate her testimony - cannot be called an investigation.

"We are profoundly disappointed that after the tremendous sacrifice she made in coming forward, those directing the FBI investigation were not interested in seeking the truth."

Political row

In another row, the two major US parties publicly disagreed on the issue of existing background checks into Judge Kavanaugh.

In a tweet, Republicans on the Senate Judiciary Committee said: "Nowhere in any of these six FBI reports, which the committee has reviewed on a bipartisan basis, was there ever a whiff of ANY issue – at all – related in any way to inappropriate sexual behavior or alcohol abuse".

That claim was disputed by eight of the ten Democrats on the committee, who wrote a letter to the committee chairman claiming the tweet was "not accurate" and had to be corrected - although noted they were 'limited' in what they could say publicly.

The suggestion that the tweet was misleading was rejected by Republicans, who insisted "nothing in the tweet is inaccurate".

A procedural vote on Judge Kavanaugh's nomination is due to take place before the full US Senate tomorrow, ahead of a possible final vote over the weekend.

With Republicans only holding a narrow two-seat majority in the upper house, the final decisions of the three 'undecided' senators will be critical for Kavanaugh's confirmation or rejection.

Meanwhile, hundreds of US law professors have signed an open letter against Kavanaugh's confirmation.

Published in the New York Times, the professors claim that President Trump's nominee "did not display the impartiality and judicial temperament requisite to sit on the highest court of our land" during his public testimony last week.