Washington (CNN) President Donald Trump said Saturday that the FBI has "free rein" to investigate his Supreme Court nominee Brett Kavanaugh, who has been accused of sexual assault and sexual misconduct.

"The FBI as you know is all over, talking to everybody ... " Trump told reporters Saturday in Washington on his way to a rally in West Virginia. "They have been all over it already. They have free rein to do whatever they have to do."

On Friday, the Senate Judiciary Committee formally requested the White House instruct the FBI to conduct a supplemental background investigation, saying it should probe "current credible allegations" against Kavanaugh.

Complying with the Senate's request, Trump directed the FBI Friday night to re-open its background investigation into Kavanaugh with the probe "limited in scope and completed in less than one week."

Republicans said it would be left up to the FBI to decide which allegations are considered credible. Republican Sens. Jeff Flake, Susan Collins and Lisa Murkowski, all key swing votes, set the terms of the investigation, three sources familiar with the matter told CNN.

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