Confidence grew among President Donald Trump’s fellow Republicans on Thursday that Brett Kavanaugh would win Senate confirmation to the US Supreme Court, after positive comments from two wavering lawmakers about an FBI report on accusations of sexual misconduct by the judge.

The report, sent by the White House to the Senate Judiciary Committee in the middle of the night, was denounced by Democrats as a whitewash that was too narrow in scope and ignored critical witnesses.

Comments by two crucial Republican senators — Jeff Flake and Susan Collins — indicated the report may have allayed concerns they had about Kavanaugh.

Republicans control the Senate by a razor-thin 51-49 margin, meaning the votes of those two could be crucial in securing Kavanaugh’s confirmation to the lifetime post on the country’s highest court.

Collins said the investigation appeared to be thorough, while Flake said he saw no additional corroborating information against Kavanaugh, although he was “still reading” it.

A previously undecided Democratic Senator, Heidi Heitkamp, said she would vote against Kavanaugh. Heitkamp’s decision left Senator Joe Manchin as the only undecided Democrat.

Even before the FBI report was given to lawmakers, Senate majority leader Mitch McConnell took steps to hold a key procedural vote as early as Friday, which could pave the way for a final vote on Kavanaugh’s confirmation over the weekend.

“It smacks of a whitewash,” Democratic Senator Richard Blumenthal told reporters, saying the report should not give political cover for Republicans to vote for Kavanaugh because “it is blatantly incomplete”.

Democratic Senator Dianne Feinstein noted that the FBI did not interview Kavanaugh himself or Christine Blasey Ford, a university professor who has accused Kavanaugh of sexual assault in 1982.

Thousands of protesters, some holding signs saying “Believe Survivors” and “Kava-Nope”, rallied in front of the Supreme Court in opposition to Kavanaugh.

Trump tweeted that the FBI report showed that the allegations against Kavanaugh were “totally uncorroborated”.

Amid the accusations of sexual misconduct against Kavanaugh, Republicans have stood by the judge. The party leadership said on Thursday the FBI report had not changed their view of Kavanaugh’s fitness for the job.

A senior Senate Republican aide said there was growing confidence that Collins, Flake and Manchin — all swing votes — would support Kavanaugh.

White House spokesperson Raj Shah said the Trump administration was “fully confident” Kavanaugh had the necessary support.

The White House believes the FBI report addressed the Senate’s questions about Kavanaugh, Shah told CNN, adding that the FBI reached out to 10 people in its investigation and “comprehensively interviewed” nine of them.