The office of U.S. Special Counsel Robert Mueller says it has referred to the FBI allegations that women were offered money to make up false claims about the investigator.
The scheme was uncovered after one woman who said she worked for Mueller decades ago told journalists she had been offered $20,000 to accuse him of sexual misconduct, spokesman Peter Carr said in a statement on October 30.
"When we learned last week of allegations that women were offered money to make false claims about the special counsel, we immediately referred the matter to the FBI for investigation," Carr added.
The statement didn't specify what the claims were.
Mueller was tasked last year to lead an investigation into Russian interference in the 2016 elections and possible interactions between President Donald Trump associates and Russian officials. The investigation has expanded to examine possible attempts by Trump to obstruct the probe.
Both Moscow and Trump deny the allegations.