Grassley has set a hearing for Monday for both Ford and Kavanaugh to testify about the incident.
Speaking through her lawyers, Ford, a research psychologist, Tuesday all but ruled out appearing at the hearing scheduled for Monday to hear her allegations.
Hirono asked during a news conference introducing a letter from 1,000 alumnae of the Holton-Arms School supporting Christine Blasey Ford, who was attending the school when she alleges Kavanaugh sexually assaulted her.
On Wednesday, a lawyer for Ford said her client was willing to cooperate with the committee, but criticized its plan to have only Ford and Kavanaugh testify. But she won't do it on Monday - the chairman's take-it-or-leave-it date - and she has certain conditions.
Katz reiterated that Ford, now a psychology professor in California, has received death threats and for safety reasons has relocated her family.
The lawyers said Ford was opposed to being questioned by outside counsel, according to Politico. Dianne Feinstein, the top Democrat on the committee, that he was setting a deadline of Friday at 10 a.m. for a decision from Ford on whether she will testify. The Hill reports: "Can Brett Kavanaugh be investigated for an attempted rape he allegedly committed over three decades ago?"
The confirmation fight comes just weeks before November 6 congressional elections in which Democrats are seeking to win control of Congress.
President Donald Trump's Republican Party has a challenge to maintain control of Congress in November's mid-term elections | AFP
Groups of protesters, majority women, clogged the lobby of Grassley's Senate office on Thursday and targeted other Republican lawmakers. "It is imperative the Judiciary Committee move forward on the Kavanaugh nomination and a committee vote be taken as soon as possible", the committee member said in a statement.
Twenty-three people were arrested Thursday morning for unlawful demonstrations. She asserted that Republicans are rushing to confirm Kavanaugh because the court's "session is going to start in October and the President wants his guy there to, he hopes, help him evade criminal or civil proceedings". She accused Kavanaugh of attacking her and trying to remove her clothing while he was drunk at a party when he was 17 years old and she was 15.
In a call Wednesday with Iowa reporters, Grassley expressed doubts she'd appear before his committee.
The back-and-forth came hours after President Donald Trump described the allegation against Kavanaugh as hard to believe and the furor surrounding it as "very unfair" to the judge.
Added Jeffress, " I can say with absolute certainty that the Democrats don't care who is telling the truth.
One of the four has yet to be publicly identified.
The Republicans on the committee know they have to give her every opportunity to tell her story but they are adamant that this is not a matter for the Federal Bureau of Investigation and that Democrats are using the case to simply stall the nomination process, our correspondent says. "But Judge Kavanaugh gets only 40 percent support from Hispanic voters and nearly no support from black voters", said Peter A. Brown, assistant director of the Quinnipiac University Poll.