CNN reports that it has confirmed that the Steel dossier on Russian ties to Donald Trump's campaign was part of its evidence to gain a secret court order.
The FBI last year used the dossier to win approval to secretly monitor a Trump associate, US officials told CNN.
The network said the dossier has also been cited by FBI Director James Comey in some of his briefings to members of Congress.
A Foreign Intelligence Surveillance Act (FISA) order was gained to monitor the communications of Carter Page, a Trump campaign adviser last year on national security.
CNN reported: "Officials familiar with the process say even if the application to monitor Page included information from the dossier, it would only be after the FBI had corroborated the information through its own investigation. The officials would not say what or how much was corroborated".
A summary of the dossier, compiled by former British spy Christopher Steel, was presented to President Barack Obama and President-elect Trump in December by top US Intelligence officials.
CNN reported: "Comey's briefings to lawmakers stand in contrast to efforts in recent months by the bureau and US intelligence agencies to try to distance themselves from the dossier. US law enforcement and intelligence officials have said US investigators did their own work, separate from the dossier, to support their findings that Russia tried to meddle in the 2016 presidential election in favour of Trump".
Page has denied meeting Russian officials named in the dossier and says he never cut any political deals with the Kremlin.