The U.S. attorney who is conducting a wide-ranging investigation of the origins of the Trump-Russia probe released a rare statement Monday saying he disagrees with conclusions of the so-called FISA report -- after DOJ Inspector General Michael Horowitz found in that review that the probe's launch largely complied with DOJ and FBI policies.

“Based on the evidence collected to date, and while our investigation is ongoing, last month we advised the Inspector General that we do not agree with some of the report’s conclusions as to predication and how the FBI case was opened,” U.S. Attorney John Durham said in a statement.

FISA REPORT: DOJ WATCHDOG RELEASES FINDINGS ON RUSSIA PROBE SURVEILLANCE

Horowitz released his report Monday saying his investigators found no intentional misconduct or political bias surrounding efforts to launch that 2016 probe and to seek a highly controversial Foreign Intelligence Surveillance Act (FISA) warrant to monitor former Trump campaign adviser Carter Page in the early months of the investigation. Still, it found that there were "significant concerns with how certain aspects of the investigation were conducted and supervised."

“I have the utmost respect for the mission of the Office of Inspector General and the comprehensive work that went into the report prepared by Mr. Horowitz and his staff,” Durham said. “However, our investigation is not limited to developing information from within component parts of the Justice Department. Our investigation has included developing information from other persons and entities, both in the U.S. and outside of the U.S.”

As Horowitz has conducted his review of DOJ actions during the Russia probe, Durham, the U.S. attorney for Connecticut, has also been conducting a wider inquiry into alleged misconduct and alleged improper government surveillance on the Trump campaign during the 2016 presidential election.

Fox News reported in October that Durham's ongoing probe has transitioned into a full-fledged criminal investigation.

Meanwhile, Attorney General William Barr ripped the FBI’s “intrusive” investigation after the release of Horowitz’s review, saying it was launched based on the “thinnest of suspicions.”

“The Inspector General’s report now makes clear that the FBI launched an intrusive investigation of a U.S. presidential campaign on the thinnest of suspicions that, in my view, were insufficient to justify the steps taken,” Barr said in a statement.

Barr expressed frustration that the FBI continued investigating the Trump campaign, even as “exculpatory” information came to the light.

“It is also clear that, from its inception, the evidence produced by the investigation was consistently exculpatory,” Barr said. “Nevertheless, the investigation and surveillance was pushed forward for the duration of the campaign and deep into President Trump’s administration.”

Former Special Counsel Robert Mueller acknowledged in his report that investigators did not find evidence of a conspiracy between Trump’s campaign and the Russians in 2016 – which the FBI probed extensively.

Barr said the FISA report shows a “clear abuse” of the surveillance process.

“In the rush to obtain and maintain FISA surveillance of Trump campaign associates, FBI officials misled the FISA court, omitted critical exculpatory facts from their filings, and suppressed or ignored information negating the reliability of their principal source,” Barr said.

He added, “The Inspector General found the explanations given for these actions unsatisfactory. While most of the misconduct identified by the Inspector General was committed in 2016 and 2017 by a small group of now-former FBI officials, the malfeasance and misfeasance detailed in the Inspector General’s report reflects a clear abuse of the FISA process.”

Monday’s FISA report dealing with the investigation into Trump’s campaign has long been expected. Horowitz in September submitted a draft of the report to Barr and the FBI so they could identify any classified information. But it had not been publicly released until now.

The release comes as Washington has been consumed with an impeachment inquiry into President Trump. The House Judiciary Committee is holding the inquiry’s latest hearing Monday, days after House Speaker Nancy Pelosi said Democrats are moving forward with plans to bring articles of impeachment against the president over his dealings with Ukraine.

Fox News’ Jake Gibson contributed to this report.