President Donald Trump said Friday that he had ordered the FBI to conduct a "supplemental investigation" into an allegation of sexual assault against Supreme Court nominee Brett Kavanaugh.

Trump said that the probe "must be limited in scope and completed in less than one week."

White House press secretary Sarah Huckabee Sanders tweeted out Trump's statement Friday afternoon.

Sanders tweet

Sanders' tweet came just hours after Sen. Jeff Flake, R-Ariz., called for a delay in Kavanaugh's final confirmation vote by up to a week to allow the FBI to investigate "credible" allegations of sexual misconduct against the Supreme Court nominee.

The announcement is a dramatic concession from Trump, who had strongly endorsed Kavanaugh in the wake of the judge's incendiary testimony before the Senate Judiciary Committee a day earlier.

Minutes before Sanders' tweet, Kavanaugh released a statement through White House deputy press secretary Raj Shah on Friday:

"Throughout this process, I've been interviewed by the FBI, I've done a number of "background" calls directly with the Senate, and yesterday, I answered questions under oath about every topic the Senators and their counsel asked me. I've done everything they have requested and will continue to cooperate."

Testifying under oath before the committee on Thursday, a visibly furious and emotional Kavanaugh had denied Christine Blasey Ford's allegation that he sexually assaulted her in the early 1980s when they were teenagers.

Ford had offered her first publicly spoken words about the alleged assault in the Senate hearing before Kavanaugh. She said an intoxicated Kavanaugh, with participation from his classmate Mark Judge, had held her down on a bed, covered her mouth and tried to disrobe her.

Kavanaugh has repeatedly denied the allegation, and told the committee, "I've never sexually assaulted anyone."

In a statement following Trump's decision, Ford's lawyer Debra Katz said that "a thorough FBI investigation is critical to developing all the relevant facts."

Ford "welcomes this step in the process, and appreciates the efforts of Senators Flake, Murkowski, Manchin and Collins — and all other senators who have supported an FBI investigation — to ensure it is completed before the Senate votes on Judge Kavanaugh's nomination," Katz said. "No artificial limits as to time or scope should be imposed on this investigation."

WATCH: Trump says Ford's testimony very compelling