President Donald Trump has mocked the testimony of Christine Blasey Ford against his Supreme Court nominee Brett Kavanaugh at a rally in Mississippi.
"What neighbourhood was it in? I don't know," Mr Trump said. "But I had one beer. That's the only thing I remember. And a man's life is in tatters."
Days earlier he had said Prof Ford was a "credible" and "compelling" witness.
Prof Ford told a Senate committee that Mr Kavanaugh assaulted her as a teenager, an allegation he denies.
Mr Trump ordered the FBI to examine the claims following the Senate testimony.
However, Prof Ford's lawyers say the FBI have not yet spoken to her and say it is "inconceivable" that the agency could conduct a thorough investigation without interviewing her.
The FBI investigation is due to be completed by Friday.
Senate Majority Leader Mitch McConnell has said the Senate must vote on confirming Mr Kavanaugh this week.
What did Mr Trump say?
He told supporters in the town of Southhaven that his political opponents had been "trying to destroy Judge Kavanaugh since the very first second he was announced".
He then launched into his mockery of Prof Ford's testimony, saying that she appeared not to remember basic details about the evening the alleged assault took place.
The audience laughed as the president said: "Thirty-six years ago this happened: I had one beer! Well, you think it was…? Nope! It was one beer.
"Oh, good. How'd you get home? I don't remember. How'd you get there? I don't remember. Where was the place? I don't remember.
"How many years ago was it? I don't know. I don't know. I don't know! I don't know! What neighbourhood was it in? I don't know.
"Where's the house? I don't know! Upstairs, downstairs, where was it? I don't know! But I had one beer. That's the only thing I remember. And a man's life is in tatters."
Prof Ford's lawyer, Michael Bromwich, described Mr Trump's words as "a vicious, vile and soulless attack" on her.
"Is it any wonder that she was terrified to come forward, and that other sexual assault survivors are as well?" he added.
Mr Trump's latest stance contrasts with the reaction he gave shortly after Prof Ford's dramatic testimony to the Senate committee last week, when he said her testimony was "very compelling" and described her as a "very fine woman".
Experts have said it is not unusual for victims of trauma to remember certain details vividly but have little recollection of other things that the brain may have accorded less significance to.
Earlier on Tuesday Mr Trump reiterated his support for Mr Kavanaugh, saying he believed the Senate would approve the judge. He told reporters that it was a "very scary time for young men in America when you can be guilty of something that you may not be guilty of".