WASHINGTON — Under pressure from key Republican senators, President Donald Trump on Friday ordered the FBI to conduct an additional background investigation of Supreme Court nominee Brett Kavanaugh, who faces several sexual misconduct allegations.

"I've ordered the FBI to conduct a supplemental investigation to update Judge Kavanaugh’s file," Trump said in a statement. "As the Senate has requested, this update must be limited in scope and completed in less than one week."

Trump's action — he said recently he had not directed the FBI to investigate because the agency didn't want to get involved — followed an extraordinary call from several key Republican senators to enlist the agency to gather information about the alleged incidents involving Kavanaugh when he was in high school and college before the Senate holds a vote on his confirmation.

The president is the only person who can order such an FBI investigation.

"The supplemental FBI background investigation would be limited to current credible allegations against the nominee and must be completed no later than one week from today," the Senate Judiciary Committee said in a statement.

Republicans had generally opposed an FBI investigation, saying Kavanaugh has been through a half dozen background checks over the years and adding that a new probe would be unlikely to shed much light on the claims because the agency doesn't reach conclusions about who's telling the truth. Democrats, on the other hand, said a fresh investigation could help unearth key facts that would be useful in trying to get to the bottom of the "he said, she said" allegations.

Earlier, Trump, when asked about a possible delay in the full Senate vote in order for the FBI to investigate, told reporters at the White House that he would defer to GOP senators.

"Whatever they think is necessary," he said. "I'm going to the let the Senate handle that. They've been doing a good job. Very professional."

There are three main public accusers of Kavanaugh:

-Christine Blasey Ford, who alleges he attacked her at a party when they were in high school, trying to remove her clothes, grinding against her and putting his hand over her mouth when she tried to scream;

-Deborah Ramirez, who told The New Yorker that Kavanaugh pulled down his pants and exposed himself to her while they were classmates at Yale University and;

-Julie Swetnick, who, in a sworn declaration, accused him of engaging in repeated lewd behavior with women at parties in the early 1980s, and of putting drugs or alcohol in punch to cause women to become inebriated so they could be "gang raped" by male partygoers.

Ford's lawyer, Debra Katz, said in a statement that her client supported the FBI investigation but does not believe there would be any time limit on it.

"A thorough FBI investigation is critical to developing all the relevant facts," Katz said. "Dr. Christine Blasey 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. No artificial limits as to time or scope should be imposed on this investigation."

Kavanaugh said in a statement Friday evening, "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."

Word of the potential new FBI involvement came just hours after Kavanaugh was approved Friday by the Senate Judiciary Committee on an 11-10 party-line vote.

During that meeting, Sen. Jeff Flake, R-Ariz., issued a surprise call for the full Senate vote to be delayed for one week to allow time for the FBI to reopen its background investigation.

Flake voted in favor of Kavanaugh during the Judiciary Committee vote, but then suggested he may not vote for Kavanaugh on the Senate floor if the FBI investigation does not take place.

Sen. Lisa Murkowski, R-Alaska, backed Flake's push for a one-week delay in the confirmation vote to give the FBI time to look into the allegations. "I think it's important that we do our due diligence and this is yet another step in that due diligence," she said.

That set in motion Trump's orders to the FBI. If Flake and one or two other GOP senators opposed moving the nomination to the Senate floor for a vote, that could stall or even doom Kavanaugh's confirmation. Sen. Susan Collins, R-Maine, who has not indicated how she intends to vote on the nomination, previously indicated she backs an FBI investigation.

Meanwhile, if the nomination eventually gets to the floor for a vote, there are four key senators, two Republicans and two Democrats, who have not yet indicated how they intend to vote. The nomination would fail if all Democrats vote no and the two Republicans on the fence defect and oppose Kavanaugh.