Mr Kavanaugh's nomination has been threatened by allegations stemming from his time in high school and college

Key Republicans are having their support for Brett Kavanaugh tested after Donald Trump mocked his Supreme Court nominee’s sexual assault accuser at a campaign rally in Mississippi.

The president joked about Dr Ford's testimony to a laughing crowd on Wednesday, criticising her for failing to remember every detail from the night she alleges Mr Kavanaugh assaulted her during a high school party nearly 36 years ago.

Meanwhile, the FBI has reportedly neared the conclusion of its probe into the embattled nominee ahead of the Senate Judiciary Committee deadline of Friday — despite numerous potential witnesses indicating they have not yet spoken with investigators from the federal agency, including Dr Ford.

Arizona Republican Jeff Flake, who forced the majority to take a one-week delay and allow for an FBI investigation into the sexual assault claims against Mr Kavanaugh, denounced the president’s comments in an interview with NBC.