Chuck Grassley of Iowa, the Republican who presided over last week's hearing as chairman of the Judiciary Committee. And Senator Joe Manchin of West Virginia, was the only Democrat to join the opposition in voting "Yes".
The FBI inquiry began last week at the direction of the White House after Republican Sen.
Democrats said the allegations were credible and deserved a full investigation, while Republicans accused Democrats of using uncorroborated allegations to scuttle or delay the nomination - leading to a stream of angry flashpoints between lawmakers.
Murkowski said she was "still reviewing" her decision.
Democratic Senator Dianne Feinstein noted that the Federal Bureau of Investigation did not interview Mr Kavanaugh himself or Christine Blasey Ford, a university professor from California who has accused Mr Kavanaugh of sexual assault in 1982.
One of the senators hinted he was open to supporting Mr Kavanaugh as party leaders set a pivotal preliminary vote for 10.30am local time on Friday. Kavanaugh also testified before the committee - and vehemently denied the allegation.
In another development, more than 2,400 law professors signed on a letter to the Senate on Thursday, saying Kavanaugh lacks judicial temperament and is disqualified from sitting on the nation's highest court, according to a Washington Post report.
Andrew Harrer/Bloomberg via Getty Images Senator Susan Collins, a Republican from ME, arrives on Capitol Hill in Washington, D.C., U.S., on Friday, Oct. 5, 2018. Lisa Murkowski of Alaska, Susan Collins of ME or Jeff Flake of Arizona. If so, that could be enough for a Trump victory.
The Republicans hold a 51-49 majority in the chamber and three of their members are thought to be undecided on President Donald Trump's candidate.
Republican Sen. Jeff Flake (R-AZ), the senator who requested the latest FBI background investigation, and his colleague Sen.
But that was about the most certain aspect of the contentious vote, other than that the outcome would be close and more protests would erupt across the Capitol complex.
It's now down to a handful of undecided senators on both sides of the aisle.
Protesters gathered outside the home of Senate Majority Leader Mitch McConnell and staged a "confirmation kegger", in the final hours before the Senate prepares for a confirmation vote for Brett Kavanaugh's embattled nomination to the Supreme Court.
"When considering a lifetime appointment to Supreme Court, we must evaluate the totality of the circumstances and record before us", Heitkamp said in a statement. "An acclaimed judge", McConnell said on the Senate floor after the report's release. "There's nothing in it that we didn't already know".
Christine Blasey Ford charged Judge, Kavanaugh's friend from Georgetown Prep, was in the room when she claims Kavanaugh pinned her to a bed, groped her and covered her mouth when she screamed during a high school party in the 1980s.
The California Democrat said that the judge's behavior showed "a man filled with anger and aggression".
Within hours of the findings being made available on Capitol Hill, some leading Republican and White House figures declared that the probe had failed to find any information to corroborate the allegations. But Democrats disputed the Republicans' assertions, especially because, they argued, the scope of the investigation was too limited.
Earlier, the FBI delivered the results of its investigation on the sexual assault allegations to U.S. senators.