WASHINGTON, Sept 30 (Reuters) - The U.S. Justice Department's internal watchdog on Thursday said he had uncovered "widespread non-compliance" with the FBI's domestic surveillance program, dealing the bureau another setback and raising questions about the accuracy of the information underpinning its wiretap warrants.

Inspector General Michael Horowitz's findings mark the latest problem uncovered since 2019, when his office first discovered the FBI had made numerous errors in its warrant applications to the Foreign Intelligence Surveillance Court as part of the early probe into contacts between President Donald Trump's 2016 campaign and Russia.

Horowitz's report on Thursday entailed an audit of the FBI's so-called "Woods Procedures" - rules the bureau follows to ensure FISA applications to the court are "scrupulously accurate."

"A failure to adhere to the Woods Procedures ... could easily lead to errors that do impact probable cause — and therefore potentially call into question the legal basis for the government’s use of highly intrusive FISA warrants," Horowitz said.