The decision by the woman, Christine Blasey Ford, came after days of uncertainty over whether she would appear at a hearing and answer questions about her accusations of sexual assault.
WASHINGTON — The woman who has accused Judge Brett M. Kavanaugh of sexually assaulting her when they were teenagers said on Saturday that she was willing to testify next week before the Senate Judiciary Committee, but asked for more time to continue negotiating the details of her appearance.
It is now up to Senator Charles E. Grassley, the chairman of the Judiciary Committee, to decide whether to grant the extra time or move ahead with a committee vote on Judge Kavanaugh’s Supreme Court nomination scheduled for Monday.
Dr. Blasey’s representatives said that she wanted to appear before the committee on Thursday, though that detail had not been finalized.
The move by Dr. Blasey, 51, a research psychologist in Northern California, came after an extended back-and-forth between her lawyers and top Judiciary Committee aides. Mr. Grassley had set 2:30 p.m. Saturday as a final deadline for Dr. Blasey to agree or decline to appear.
Testimony by Dr. Blasey would set up a potentially explosive showdown after days of uncertainty over whether she would appear at a hearing. It could also greatly complicate matters for Judge Kavanaugh, who has vigorously denied Dr. Blasey’s allegations and just last week seemed destined for confirmation.
The Senate majority leader, Mitch McConnell of Kentucky, has said that he has enough votes, but with at least two Republicans in the Senate undecided and with the party holding only a 51-to-49 majority, confirmation is hardly assured.
Dr. Blasey’s accusations, coming just days before the Judiciary Committee was initially set to vote on Judge Kavanaugh, have rocked official Washington, evoking memories of the 1991 confirmation of Justice Clarence Thomas, who was accused of sexual harassment by the law professor Anita Hill. They have further energized Democrats, and women particularly, in a midterm election in which Republicans are struggling to court the female vote.
Over the past week, Dr. Blasey has become a cultural touchstone for women around the country in the era of the #MeToo movement. A hashtag, #IBelieveChristine, has sprung up on Twitter, and survivors of sexual assault are set to rally in New York on Monday. A Facebook post promoting the rally said that “New York City stands with Dr. Blasey Ford and all sexual assault survivors.”
The intense attention on Dr. Blasey’s accusation continued to reverberate on Capitol Hill on Saturday in unexpected ways. A communications adviser to Mr. Grassley, who had joined the Judiciary Committee temporarily to help shape messaging around Judge Kavanaugh’s confirmation, stepped down from his position after NBC News raised questions about an accusation that he sexually harassed a co-worker in a previous political job.
The adviser, Garrett Ventry, said the sexual harassment claim against him was false. A spokesman for the committee, Taylor Foy, noted the denial of wrongdoing but said that Mr. Ventry had decided to step aside “to avoid causing any distraction from the work of the committee.”
