Republicans mounted a combative, co-ordinated drive Monday to salvage Brett Kavanaugh's U.S. Supreme Court nomination as they fought to keep a second woman's allegation of long-ago sexual misconduct from derailing his confirmation.

President Donald Trump leapt to his defence and the Senate's top Republican accused Democrats of a "smear campaign."

In an unusual strategy for a Supreme Court nominee, Kavanaugh, 53, now a judge on the District of Columbia Circuit Court of Appeals, sat for an interview along with his wife late Monday on the conservative Fox News Channel.

I'm not going to let false accusations drive us out of this process. - Brett Kavanaugh , Supreme Court nominee

Careful not to assail Ford but firm in his denial, he said, "I am not questioning and have not questioned that perhaps Dr. Ford at some point in her life was sexually assaulted by someone at some place, but what I know is I've never sexually assaulted anyone."

He also said he's never considered walking away from the opportunity to join the Supreme Court.

"I'm not going to let false accusations drive us out of this process and we're looking for a fair process where I can be heard and defend my integrity, my lifelong record," he said. "My lifelong record of promoting dignity and equality for women, starting with the women who knew me when I was 14 years old. I'm not going anywhere."

In the run-up to an appearance by Kavanaugh and his main accuser at a Senate hearing later this week, the Republicans took an aggressive stance with his nomination dangling precariously. The similar tones and wording they used suggested a concerted effort to undermine the women's claims, portray an image of unity among Republican senators and press ahead to a confirmation vote.

'Totally political'

Trump called the accusations "totally political" and among "the single most unfair, unjust things to happen to a candidate for anything." Senate majority leader Mitch McConnell, a Republican from Kentucky, angrily accused Democrats of slinging "all the mud they could manufacture."

Senate Democratic leader Chuck Schumer, retorted: "If you really believe they are a smear job, why don't you call for FBI investigation?" Schumer accused the Republicans of "a rush job to avoid the truth."

Trump has made clear he won't order an FBI investigation of the allegations. And McConnell said Thursday's judiciary committee hearing would proceed and that full Senate consideration would follow "in the near future," though he mentioned no date.

U.S. President Donald Trump speaks to reporters at United Nations headquarters early Monday in New York. Trump and the White House defended Kavanaugh, but it's not clear if a planned Senate committee hearing will still take place on Thursday as scheduled in the wake of new allegations. (Caitlin Ochs/Reuters)

Kavanaugh was asked in the Fox News interview whether the FBI should investigate the matter, but he declined to directly answer the question.

He also wrote in a letter to the committee planning the hearing where he and his first accuser, a psychology professor at Palo Alto University named Christine Blasey Ford, will both appear, that his opponents were launching "smears, pure and simple."

On Sunday, The New Yorker magazine reported that Deborah Ramirez described an alcohol-heavy Yale dormitory party in the 1980s at which she said Kavanaugh exposed himself, placed his penis in her face and caused her to touch it without her consent.

Senate vote in question

Despite the forceful rhetoric by Kavanaugh and his Republican supporters, it remained unclear how three moderate Republican senators — Susan Collins of Maine, Arizona's Jeff Flake and Alaska's Lisa Murkowski — would react to the latest accusation. With the Republicans' Senate control hanging on a razor-thin 51-49 margin, defections by any two Republican senators would seal Kavanaugh's fate if all Democrats vote "no."

Proceeding with Kavanaugh seems to give Republicans their best shot at filling the Supreme Court vacancy — and giving the court an increasingly conservative tilt — before November's midterm elections, when Republican Senate control is in play.

Even if Republicans lose their Senate majority, they could still have time to confirm a nominee in a post-election lame duck session, but the Republican Party has not indicated that is under consideration. Delaying Kavanaugh's confirmation could give time for doubts about him to take root or for fresh accusations to emerge.

Pushing forward with Kavanaugh has risks of its own, besides an embarrassing defeat for Trump and the Republican Party. His nomination and the claims of sexual misconduct dating from his teenage years have stirred up women and liberal voters whose antipathy to Republicans has already been heightened by Trump's policies and his own fraught history of alleged sexual transgressions.

More than 120 people protesting Kavanaugh were arrested Monday outside Collins's Capitol Hill office. Many wore black "Be A Hero" shirts and chanted slogans including, "We will not be silenced."

Capitol Hill Police stand in front of protesters speaking out against Kavanaugh outside the office of Sen. Susan Collins, a key Republican vote in the confirmation process, in Washington on Monday. Dozens were arrested. (Alex Brandon/Associated Press)

Protests on Capitol Hill were buttressed by walkouts away from Washington in support of Ford and Ramirez that were staged by dozens of liberal groups. The campaign was promoted on Twitter under the hashtag #BelieveSurvivors, and several Democrats in Congress — including members of the Senate judiciary committee vetting Kavanaugh — posted photos in support.

A week ago, Ford told the Washington Post that at a high school house party in the early 1980s, a drunk Kavanaugh forced her into a bedroom where he pinned her on a bed, tried removing her clothes and muffled her mouth to prevent screams before she escaped.

With increasing intensity, Republicans have attacked the credibility of both women's accounts. They note that neither the accusers nor news organizations have found people willing to provide corroboration, even though Ford and Ramirez have both named people who they said were present at the alleged incidents.

In a letter made public on Monday to the Senate committee's Republican chairman, Sen. Chuck Grassley, Ford said she had faced death threats and was relying on her lawyers and Grassley to agree to conditions that will allow her "to testify in a fair setting."

"While I am frightened, please know, my fear will not hold me back from testifying and you will be provided answers to all of your questions," Ford wrote.

Ramirez, who told The New Yorker that she had been drinking at the time, was initially reluctant to speak publicly "partly because her memories contained gaps," the magazine said. After "six days of carefully assessing her memories and consulting with her attorney," she felt confident enough to go public, the report said.

No comment from 2nd accuser

The Associated Press tried reaching Ramirez at her home in Boulder, Colo. A sign posted on her front door indicated she would have no comment.

White House counsellor Kellyanne Conway held a conference call with supporters Monday morning during which, according to a participant who spoke on condition of anonymity to describe the private call, she said there was a "vast left-wing conspiracy" to prevent Kavanaugh from winning confirmation.

Also jumping into the fray was the attorney who represents porn actress Stormy Daniels in her legal fight with Trump. Lawyer Michael Avenatti said he was representing a woman with information about high school-era parties attended by Kavanaugh and urged the Senate to investigate.

My client is not Deborah Ramirez. —@MichaelAvenatti

Avenatti, who has said he's considering a 2020 Democratic presidential bid, told The Associated Press that he will disclose his client's identity in the coming days and that she is prepared to testify before the committee, as well as provide names of corroborating witnesses.

— With files from Reuters and CBC News