Trump called the allegations against Kavanaugh "false accusations", but stopped short of calling his accusers liars.
"If I thought he was guilty of something like this, yes, sure", Mr Trump said at a press conference on the sidelines of the UN General Assembly in NY.
Republicans acknowledged that much was riding on Kavanaugh's performance.
The nine-member Supreme Court is the final word on United States law, including highly contentious social issues and challenges to government policy. "This is what traumatized me the most and had the most lasting impact on my life". There is no question in my mind that Mark Judge has significant information concerning the conduct of Brett Kavanaugh during the 1980s, especially as it relates to his actions toward women.
Kavanaugh is being challenged on multiple fronts by his accusers, former classmates and college friends.
Kavanaugh replied that he doesn't even know Swetnick and that her accusations are "from the Twilight Zone".
Dr Ford, a university professor in California, has accused Mr Kavanaugh of sexually assaulting her in 1982 when they were both high school students in Maryland. He added, "Obviously with this one we have a contact and our lawyers are on it right now".
Kavanaugh has strongly denied her claims as well as allegations by two other accusers. "I never committed sexual assault". You know why? Because I've had a lot of charges made against me.
Ford began her testimony by describing the anxiety accompanying her appearance before the committee.
According to transcripts from interviews between committee investigators and Kavanaugh, the Supreme Court nominee was asked about two other accusations received by Senate offices.
Kavanaugh accuser Ford offers Senate 4 people who corroborate assault claims
About 200 people gathered in front of the Supreme Court building in Washington , chanting: "I believe Christine Ford."U.S. Capitol Police reported that 128 people were arrested on charges of unlawfully demonstrating in Senate office buildings".
Swetnick and Avenatti did not immediately respond to requests for comment.
The woman who accuses President Donald Trump's Supreme Court pick of sexual assault at a high school party will testify Thursday that she feared Brett Kavanaugh would rape her.
He made the comments at a news conference in NY a day before Judge Brett Kavanaugh was set to testify before the Senate Judiciary Committee amid multiple accusations of sexual misconduct. "I ask that she bring those filings forward so that we can learn date, time, and place!" he said.
Kavanaugh categorically denied Swetnick's claims.
She said it took a "public outcry" for Ford to get to come before the Judiciary panel. "The uproarious laughter between the two, and their having fun at my expense", Ford said, referring to Brett Kavanaugh and his friend Mark Judge, who she says was in the room.
The previously unknown interviews could add a new layer to the evolving saga on the eve of a possible explosive hearing between Kavanaugh and Ford, though it's unknown whether the men's claims are being taken seriously. "I am terrified. I am here because I believe it is my civic duty to tell you what happened to me while Brett Kavanaugh and I were in high school", Ford said, reading from her prepared testimony.
She also said Kavanaugh was present at a house party where she was drugged and "gang raped".
Republicans hold a 51-49 advantage in the Senate and can't afford more than one defection to ensure confirmation without Democratic support.
She spoke about the alleged incident in New Yorker magazine and has said she is willing to co-operate with any investigation.