United States President Donald Trump is directing the FBI to launch a supplemental investigation into his Supreme Court nominee Brett Kavanaugh at the request of the Senate Judiciary Committee.

Key points: Senator Flake said Ms Ford gave "compelling testimony" but Mr Kavanaugh provided "a persuasive response"

Senator Flake said Ms Ford gave "compelling testimony" but Mr Kavanaugh provided "a persuasive response" Mr Trump's fellow Republicans hold a slim Senate 51-49 majority

Mr Trump's fellow Republicans hold a slim Senate 51-49 majority Democrats have urged a delay in the confirmation process to allow for an FBI investigation

Mr Trump said in a statement that the updated investigation, which comes in response to sexual misconduct allegations, "must be limited in scope" and "completed in less than one week".

The decision marks a reversal for the administration, which had argued that Mr Kavanaugh had already been vetted.

Mr Kavanaugh has adamantly denied the allegations.

Christine Blasey Ford, the woman who has accused Mr Kavanaugh of sexual assault, welcomed an FBI investigation into the allegations, one of her lawyers has said.

"No artificial limits as to time or scope should be imposed on this investigation," Debra Katz, an attorney for Ford, said in a statement.

Mr Trump's announcement comes after a flurry of last-minute negotiations, in which the Senate Judiciary Committee advanced Mr Kavanaugh's nomination for the Supreme Court following an agreement to a late call from Republican Senator Jeff Flake of Arizona for a one-week investigation into sexual assault allegations against the Supreme Court nominee.

Sorry, this video has expired Senator Flake proposes a one-week FBI investigation into Mr Kavanaugh.

The announcement came a day after Mr Kavanaugh and his accuser, Ms Ford, testified in an emotional, hours-long hearing.

Mr Kavanaugh angrily denied the allegations that he assaulted Ms Ford while they were both in high school, while she said she was "100 per cent" certain he was her attacker.

Senator Flake, a key moderate Republican, was at the centre of the drama and uncertainty.

On Friday morning, he announced that he would support Mr Kavanaugh's nomination.

Senator Flake, who had previously raised concerns about the allegations against Mr Kavanaugh, said on Friday Ms Ford gave "compelling testimony" but Mr Kavanaugh provided "a persuasive response".

'Tell me that it doesn't matter what happened to me'

Soon after Senator Flake made his announcement, he was confronted in an elevator while on his way to the committee meeting by two protesters who said they were sexual assault survivors.

Sorry, this video has expired Two protestors confront Senator Flake in an elevator.

"Look at me and tell me that it doesn't matter what happened to me," said 23-year-old Maria Gallagher.

"That's what you're telling all women in America — that they don't matter, they should just keep it to themselves."

"I need to go to my hearing. I've issued my statement," Senator Flake said.

After huddling privately with his colleagues, Senator Flake announced that he would vote to advance Mr Kavanaugh's nomination to the full Senate only if the FBI were to investigate the allegations against the judge.

Democrats have been calling for such an investigation, though Republicans and the White House have insisted it's unnecessary.

'Calculated and orchestrated political hit'

Sorry, this video has expired Brett Kavanaugh denied ever assaulting Christine Blasey Ford

If confirmed, Mr Kavanaugh would consolidate conservative control of the nation's highest court and advance President Donald Trump's broad effort to shift the American judiciary to the right.

The committee's meeting came the morning after a jarring and emotional hearing into sexual misconduct allegations against Mr Kavanaugh that gripped the country.

Republican committee chairman Chuck Grassley said he found both Ms Ford's and Mr Kavanaugh's testimony "credible," but added, "There's simply no reason to deny Judge Kavanaugh a seat on the Supreme Court on the basis of evidence presented to us."

Committee members had little time to review Thursday's extraordinary testimony from Mr Kavanaugh and Ms Ford, who accused him of sexually assaulting her when they were high school students in 1982.

Sorry, this video has expired Christine Blasey Ford testified that Brett Kavanaugh laughed while assaulting her.

Mr Kavanaugh accused Democrats of a "calculated and orchestrated political hit", adding he was the victim of a "grotesque and obvious character assassination".

Senator Dianne Feinstein, the committee's senior Democrat, called Mr Kavanaugh's remarks unseemly for a judicial nominee.

"This was someone who was aggressive and belligerent. I have never seen someone who wants to be elevated to the highest court in the country behave in that manner.

"In stark contrast, the person who testified yesterday and demonstrated a balanced temperament was Dr Ford," Ms Feinstein said.

Mr Kavanaugh could be the deciding vote on several contentious legal issues if he is confirmed to the nine-member court, with disputes involving abortion, immigration, gay rights, voting rights and transgender troops possibly heading to the court soon.

Senator Flake was confronted in an elevator while on his way to the committee meeting by two protesters who said they were sexual assault survivors. ( AP: Pablo Martinez Monsivais )

The court begins its next term on Monday, down one justice after the retirement of conservative Anthony Kennedy effective in July. Mr Trump nominated Mr Kavanaugh to replace Mr Kennedy.

Senate Majority Leader Mitch McConnell is hoping the full Senate will quickly approve Mr Kavanaugh, possibly as soon as Tuesday.

Ms Ford has emerged in the eyes of many American women as a compelling figure in the #MeToo movement against sexual harassment and assault.

Anti-Kavanaugh protests during the hearings saw 88 people arrested and charged with unlawfully crowding or obstructing.

Police said 81 were arrested on Friday morning outside a committee meeting in the Dirksen office building, and seven more in the afternoon in a separate protest at the Hart building.

Protesters gather inside the Hart Senate Office Building on Capitol Hill in Washington as hearings take place. ( AP: Patrick Semansky )

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