A procedural vote in the Senate was scheduled for Friday, with a possible final confirmation vote over the weekend.

WASHINGTON — A high-stakes partisan row quickly broke out Thursday over a confidential FBI report about allegations that Brett Kavanaugh sexually abused women three decades ago, with Republicans claiming investigators found "no hint of misconduct" and Democrats accusing the White House of slapping crippling constraints on the probe.

The battling commenced as the conservative jurist's prospects for winning Senate confirmation to the Supreme Court remained at the mercy of five undeclared senators, with an initial, critical vote looming Friday. It followed the FBI's early-morning release of its investigation, which President Donald Trump reluctantly ordered under pressure from a handful of senators.

"There's nothing in it that we didn't already know," Grassley contended, basing his comment on a briefing he said he'd received from committee aides. He added, "This investigation found no hint of misconduct."

In a potential sign of momentum for Kavanaugh, Sen. Jeff Flake, R-Ariz., told CNN that "we've seen no additional corroborating information" and said the investigation had been comprehensive. Flake, who's not stated his position on the nomination, was among three Republicans who pressed Trump to order the renewed FBI background check.

Another GOP lawmakers who has publicly taken no stance, Susan Collins of Maine, called the probe "a very thorough investigation" and said she'd read the documents later. Alaska's Lisa Murkowski said she'd read the report.

Other Republicans who'd already voiced support for Kavanaugh echoed Grassley, saying after a briefing that there'd been no corroboration of wrongdoing by Kavanaugh. Said Sen. Lindsey Graham, R-S.C., "The senators who requested the supplemental background check got what they requested, and I am ready to vote."

Democrats Heidi Heitkamp of North Dakota and Joe Manchin of West Virginia have also not declared how they will vote.

Top Democrats fired back at Grassley after getting their own briefing.

The Judiciary panel's top Democrat, Dianne Feinstein of California, said it appeared that the White House had "blocked the FBI from doing its job." She said that while Democrats had agreed to limit the probe's scope, "we did not agree that the White House should tie the FBI's hands."

Senate Majority Leader Mitch McConnell, R-Ky., has already started a process that will produce a crucial test vote in his polarized chamber Friday on Kavanaugh's fate. Should Republicans get the majority of votes they need — and Vice President Mike Pence is available to cast the tie-breaker, if necessary — that would set up a decisive roll call on his confirmation, likely over the weekend.

Several senators said 10 witnesses were interviewed for the report. One senator said it was about 50 pages long.

Sen. John Kennedy, R-La., said agents reached out to 10 but spoke only to nine. He said five were witnesses connected to accusations by Christine Blasey Ford and four involved a separate claim by Deborah Ramirez.

Feinstein complained Thursday that agents had not interviewed Kavanaugh or Ford, who has testified that he sexually attacked her in a locked bedroom during a high school gathering in 1982. Feinstein also said attorneys for Ramirez, who's claimed Kavanaugh exposed himself to her when both were Yale freshmen, had no indication the FBI had reached out to people she'd offered for corroboration.

Grassley said the FBI could not "locate any third parties who can attest to any of the allegations," and he said there is "no contemporaneous evidence." He provided no specifics.

Senate Minority Leader Chuck Schumer, D-N.Y., said Democrats' fears that the "very limited process" laid out for the investigation would restrain the FBI "have been realized."

He also said, "I disagree with Sen. Grassley's statement that there was no hint of misconduct." Neither side provided any detail about what the report said, constrained by years-old arrangements that require the results of FBI background checks to remain confidential.

Earlier, White House spokesman Raj Shah rebuffed Democrats' complaints, saying, "What critics want is a never-ending fishing expedition into high school drinking." He said the FBI reached out to 10 people and interviewed nine, including "several individuals at the request of the Senate, and had a series of follow-up interviews ... following certain leads."

While the FBI interviews were to focus on sexual assault allegations, Democrats have also questioned Kavanaugh's drinking habits during high school and college and dishonest comments they say he has made about his background. Kavanaugh has said stories of his bad behavior while drinking are exaggerated.

Three women have accused him of sexual misconduct in separate incidents in the 1980s. Kavanaugh, 53, now a judge on the powerful District of Columbia Circuit Court of Appeals, has denied the claims.

The White House received the FBI report around 3 a.m. Thursday.

Trump weighed in hours later in a tweet in which he denounced what he called "the harsh and unfair treatment" of Kavanaugh. "This great life cannot be ruined by mean" and "despicable Democrats and totally uncorroborated allegations!"

The harsh and unfair treatment of Judge Brett Kavanaugh is having an incredible upward impact on voters. The PEOPLE get it far better than the politicians. Most importantly, this great life cannot be ruined by mean & despicable Democrats and totally uncorroborated allegations! — Donald J. Trump (@realDonaldTrump) October 4, 2018