The Justice Department's internal watchdog will tell Congress on Wednesday that he is concerned that “so many basic and fundamental errors" were made by the FBI as it investigated ties between the Trump campaign and Russia.

Michael Horowitz's testimony before the Senate Judiciary Committee comes two days after the release of a report that identified significant problems with applications to receive and renew warrants to eavesdrop on a former Trump campaign aide in 2016 and 2017. Despite those problems, the report also found that the FBI's actions were not motivated by partisan bias and that the investigation was opened for a proper cause.

Horowitz will tell senators that the FBI failed to follow its own standards for accuracy and completeness when it sought a warrant to monitor the communications of ex-campaign aide Carter Page.

Attorney General William Barr adjusts his glasses while speaking to the National Association of Attorneys General, Tuesday, Dec. 10, 2019, in Washington. (AP PhotoJacquelyn Martin)

Attorney General William Barr adjusts his glasses while speaking to the National Association of Attorneys General, Tuesday, Dec. 10, 2019, in Washington. (AP PhotoJacquelyn Martin)

“We also identified what we believe is an absence of sufficient policies to ensure appropriate Department oversight of significant investigative decisions that could affect constitutionally protected activity," Horowitz will say, according to his prepared remarks as released by the committee before the hearing.

The report has produced sharp partisan divisions. Attorney General William Barr, a vocal defender of President Donald Trump, said the FBI investigation was based on a “bogus narrative." Democrats seized on the finding that the probe was not tainted by political motivations.

President Donald Trump disembarks Marine One helicopter upon arrival at the White House Tuesday, Dec. 10, 2019, in Washington, from a campaign rally in Hershey, Pa. (AP PhotoManuel Balce Ceneta)

President Donald Trump disembarks Marine One helicopter upon arrival at the White House Tuesday, Dec. 10, 2019, in Washington, from a campaign rally in Hershey, Pa. (AP PhotoManuel Balce Ceneta)