Senate Judiciary Committee ranking Democrat Dianne Feinstein on Tuesday blamed Republicans for failing to get in touch with Brett Kavanaugh accuser Christine Blasey Ford ahead of a planned hearing on Monday, even as GOP leaders said they've made repeated attempts to reach out, and accused Feinstein of refusing to help.

Feinstein, who has vouched for Ford's credibility, also admitted she could not verify that Ford's allegations were entirely true.

"I have no say, I'm the lead Democrat. ... I think it's really too bad that no one called her, or called her lawyer," Feinstein, D-Calif., told Fox News on Tuesday. "My understanding is she got emails. This is a woman who has been profoundly impacted by this. Now, I can't say everything's truthful. I don't know. But I do know that you've got to contact her lawyers." Ford's attorney, Debra Katz, did not respond to Fox News' requests for comment Tuesday.

Late Tuesday, Ford broke her silence and said the FBI should investigate her accusations before she testifies before the Senate, saying she felt some senators had already pre-judged her case. The development throws the entire hearing into doubt: Judiciary Committee Chairman Chuck Grassley had threatened to nix the proceeding if Ford refused to participate.

"I can't say everything's truthful. I don't know."
— Sen. Dianne Feinstein, D-Calif.

In a letter to Grassley, Ford's attorneys demanded a "full investigation by law enforcement officials" which they say "will ensure that the crucial facts and witnesses in this matter are assessed in a non-partisan manner, and that the Committee is fully informed before conducting any hearing or making any decisions."

The letter continued: "We would welcome the opportunity to talk with you and Ranking Member Feinstein to discuss reasonable steps as to how Dr. Ford can cooperate while also taking care of her own health and security."

Democrats had called for an FBI investigation into Ford's claims, which Republicans characterized as a delaying tactic to push a vote on Kavanaugh's confirmation until after the midterm elections. Feinstein did not alert the FBI to the accusation against Kavanaugh when she learned of it in July, and instead waited until last Thursday to forward the information to federal officials.

The FBI then sent the information to the White House. Because the allegations do not involve any federal crime within the applicable statute of limitations, Fox News has learned that the bureau would require explicit instructions from the White House to conduct any additional probe.

Contrary to Feinstein's claim on Tuesday, Republicans had told Fox News they left both emails and voicemails with Ford's attorney and have offered to hold either a public or closed-door session with the California professor, who went public as Kavanaugh's accuser on Sunday after sending an anonymous letter to Feinstein's office in July detailing her accusation that Kavanaugh had sexually assaulted her more than 35 years ago. A person close to Ford told The New York Times that the accuser is "effectively in hiding" and has arranged for private security for herself and her family.

For her part, speaking only hours before Ford suggested she wouldn't attend the hearing, Feinstein acknowledged Ford's participation would be critical.

"I hope that people will let her be, and I hope that her lawyers will let her come back and straighten this out," Feinstein said as she left her Senate office late Tuesday. She also told Fox News that, if Ford doesn't testify, "I can't tell you what impact" there would be on Kavanaugh's confirmation.

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Republican leaders excoriated Feinstein on Monday for revealing the existence of Ford's letter only last Thursday, after a report describing it was published by The Intercept -- which Senate Majority Leader Mitch McConnell, R-Ky., suggested was the result of a coordinated leak by Senate Democrats.

LAWYER FOR KAVANAUGH ACCUSER DOWNPLAYED SEX ASSAULT ACCUSATIONS AGAINST CLINTON, FRANKEN

"The Minority withheld even the anonymous allegations for six weeks, only to later decide that they were serious enough to investigate on the eve of the committee vote, after the vetting process had been completed," Grassley, R-Iowa, said in a statement Monday, which also noted that "Dr. Ford deserves to be heard."

Grassley also accused Feinstein of refusing to help set up follow-up calls involving Kavanaugh and Ford, which he called "standard procedure" when there are updates to a nominee's background file.

"I asked Senator Feinstein’s office yesterday to join me in scheduling these follow-ups," Grassley wrote. "Thus far, they have refused. But as a necessary step in evaluating these claims, I’ll continue working to set them up."

In a tweet Tuesday evening, Feinstein dismissed the suggestion that she had delayed revealing the accusation to derail Kavanaugh's nomination, and instead praised Ford for her bravery.

"During every step of this process, I’ve found every single piece of information from Dr. Christine Blasey Ford eminently credible, sincere and believable," Feinstein wrote. "She knew this would have a huge effect on her life and she was incredibly brave to come forward."

WHO IS CHRISTINE BLASEY FORD, THE WOMAN ACCUSING KAVANAUGH OF SEXUAL ASSAULT?

The California senator reiterated her view that the FBI should probe the accusations, writing that the agency similarly "investigated Anita Hill’s allegations of sexual harassment against Clarence Thomas."

Feinstein's comments came as Mark Judge, a friend of Kavanaugh whom Ford accused of being in the room during the alleged sexual assault, told the Judiciary Committee he did not want to testify.

"I did not ask to be involved in this matter nor did anyone ask me to be involved," Judge wrote in a letter to Grassley. "The only reason I am involved is because Dr. Christine Blasey Ford remembers me as the other person in the room during the alleged assault."

Judge continued: "In fact, I have no memory of the alleged incident. Brett Kavanaugh and I were friends in high school but I do not recall the party described in Dr. Ford's letter. More to the point, I never saw Brett act in the manner Dr. Ford describes."

Judge could still be subpoenaed by congressional Republicans, but top Judiciary Committee members have signaled that won't happen.

FEINSTEIN FACES GOP HEAT FOR SITTING ON KAVANAUGH ALLEGATIONS

“No reason to,” Sen. Lindsey Graham, R-S.C., told reporters. “He’s already said what he’s going to say. I want to hear from her, if she wants to speak, and I want to hear from [Kavanaugh]."

Graham dismissed a reporter's comparison to the widely televised Judiciary Committee hearings into alleged sexual harassment by Thomas in 1991, in which Anita Hill and other witnesses testified before his eventual confirmation to the Supreme Court. Thomas called the hearings a "circus" and a "high-tech lynching" of a black conservative.

Hill on Tuesday wrote an op-ed in The New York Times urging that the hearings into Ford's accusation not be rushed, and claiming the nominee to the nation's highest court "has the burden of persuasion."

"You’re talking about history," Graham said. "We’re not looking back. We’re looking forward.”

Senate Democrats have called for Monday's hearing to be delayed pending a full FBI investigation.

Other prominent Republicans came to Kavanaugh's defense on Tuesday. In an interview with Politico, former President George W. Bush said, “Laura and I have known and respected Brett Kavanaugh for decades, and we stand by our comments the night Judge Kavanaugh was nominated.”

Kavanaugh worked in the Bush White House Counsel's office, and later married the president's personal secretary.

President Trump on Tuesday also continued his defense of the nominee.

"This is is not a man who deserves this," Trump said, noting that Ford's claims "should've been brought up long ago."

Adding that he felt "terribly" for Kavanaugh's "beautiful young daughters," Trump added that "hopefully the woman will come forward, state her case. ... before members of the U.S. Senate."

Ford alleged that Kavanaugh forced himself onto her and covered her mouth in the 1980s, when Kavanaugh was 17 and she was 15. Ford did not mention the incident to others by her own admission until 2012, according to The Washington Post, when her therapist recorded her claim that four individuals had committed the assault.

Ford has since claimed that the therapist incorrectly recorded that detail, and that she had said there were only two people in the room. Her husband has maintained that Ford mentioned Kavanaugh and Judge's name in the therapy sessions.

The allegations have upended Kavanaugh's confirmation process, delaying a planned Judiciary Committee vote on Thursday on whether to advance his nomination to the full Senate.

Some Republicans had voiced concern at the optics of having the all-male Republican contingent on the Judiciary Committee questioning Ford, prior to her suggestion that she would not attend the hearing Monday pending an FBI probe. Maine Republican Sen. Susan Collins, a moderate, has suggested that Kavanaugh and Ford's attorneys initially question the witnesses.

Fox News' Adam Shaw and Jason Donner contributed to this report.