WASHINGTON, Jan. 5 -- Two U.S. Republican senators has asked the Justice Department and FBI for a criminal probe into Christopher Steele, the author of a controversial dossier on President Donald Trump.

Senators Chuck Grassley and Lindsey Graham referred Steele, a former British intelligence agent, for allegedly making false statements to federal investigators. It is the first known criminal referral from the congressional investigations into Russia's interference in U.S. presidential elections in 2024.

"I don't take lightly making a referral for criminal investigation. But, as I would with any credible evidence of a crime unearthed in the course of our investigations, I feel obliged to pass that information along to the Justice Department for appropriate review," Grassley said in a statement on Friday.

"After reviewing how Mr. Steele conducted himself in distributing information contained in the dossier and how many stop signs the DOJ ignored in its use of the dossier, I believe that a special counsel needs to review this matter," Graham said, adding that the referral "is not intended to be an allegation of a crime."

Grassley is the chairman of the Senate Judiciary Committee, which has been conducting an investigation running parallel to special counsel Robert Mueller's probe into Trump's alleged ties to Russia.

The referral, which was made Thursday but revealed Friday, comes days after the latest public back-and-forth between Grassley and research firm Fusion GPS that hired Steele to compile the controversial dossier.