WASHINGTON (AP) — The FBI was justified in opening its investigation into ties between the Trump presidential campaign and Russia  and did not act with political bias, the Justice Department's internal watchdog declared Monday, undercutting President Donald Trump's repeated claims that he has merely been the target of a "witch hunt."

The long-awaited report rejected theories and criticism spread by Trump and his supporters, though it also found "serious performance failures" up the bureau's chain of command that are likely to be cited by Republican allies as the president faces a probable impeachment vote this month.

The review by Justice Department Inspector General Michael Horowitz found that the FBI was authorized to open the investigation to protect against a potential national security threat. Information compiled by former British spy Christopher Steele, a focus of Republican criticism, "played no role in the Crossfire Hurricane opening," the report said, using the name the FBI gave its investigation.

And the report ruled out political bias in the decision to investigate ties between the Trump campaign and Russia, a frequent contention by Trump.

But the inspector general identified 17 "significant inaccuracies or omissions" in applications for a warrant from the secretive Foreign Intelligence Surveillance Court to monitor the communications of former Trump campaign adviser Carter Page and subsequent warrant renewals, although it also found the bureau was justified in eavesdropping on Page. The errors, the watchdog said, resulted in "applications that made it appear that the information supporting probable cause was stronger than was actually the case."

Some of that information came from Steele. The watchdog found that the FBI had overstated the significance of Steele's past work as an informant, omitted information about one of his sources whom Steele had called a "boaster" and who Steele said "may engage in some embellishment."

Republicans have long criticized the process since the FBI relied in part on opposition research from Steele, whose work was financed by Democrats and Hillary Clinton's presidential campaign and that fact was not disclosed to the judges who approved the FISA warrant.

The report's release, coming the same day as a House Judiciary Committee impeachment hearing centered on the president's interactions with Ukraine, brought fresh attention to the legal and political investigations that have entangled the White House from the moment Trump took office.

Political divisions were evident in responses to the report.

 Senate Democratic leader Chuck Schumer said it makes clear that the basis for the FBI's investigation was "valid and without political bias." Trump, in remarks at the White House, claimed it showed "an attempted overthrow and a lot of people were in on it."

The president has repeatedly said he is more eager for the report of John Durham, the hand-picked prosecutor selected by Attorney General William Barr to conduct a separate review of the Russia probe.

Barr and Durham both rejected the inspector general's conclusion that there was sufficient evidence to open the FBI investigation. The attorney general's reaction was especially unusual in that the head of the Justice Department typically would not take issue with an internal investigation that clears a department agency of serious misconduct.

"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.

Durham, in a brief statement, said he had informed the inspector general that he also didn't agree with the conclusion that the inquiry was properly opened, and suggested his own investigation would back up his disagreement.

In an interview with The Associated Press, FBI Director Chris Wray noted the report's conclusion that political bias did not taint the opening of the investigation, or the steps that followed. But Wray said the inspector general found problems that are "unacceptable and unrepresentative of who we are as an institution." The FBI is implementing more than 40 corrective actions, he said.

The FBI's Russia investigation, which was ultimately taken over by special counsel Robert Mueller, began in July 2016 after the FBI learned that a former Trump campaign aide, George Papadopoulos, had been saying before it was publicly known that Russia had dirt on Democratic opponent Clinton in the form of stolen emails. Those emails, which were hacked from Democratic email accounts by Russian intelligence operatives, were released by WikiLeaks in the weeks before the election in what U.S. officials have said was an effort to harm Clinton's campaign and help Trump.

Months later, the FBI sought and received the Page warrant. Officials were concerned that Page was being targeted for recruitment by the Russian government, though he has denied wrongdoing and has never been charged with a crime.

The inspector general also found that an FBI lawyer is suspected of altering an email to make it appear that an official at another government agency had said Page was not a source for that agency, even though he was.

Agents were concerned that if Page had worked as a source for another government agency, the FBI would have needed to tell the surveillance court about that, the report said, and contacted the other agency to obtain additional information. But the FBI lawyer "did not accurately convey, and in fact altered, the information he received from the other agency," the report said.

The lawyer is not identified by name in the report, but people familiar with the situation have identified him as Kevin Clinesmith. The inspector general's report said officials notified the attorney general and FBI director and provided them with information about the altered email.

The inspector general conducted more than 170 interviews involving more than 100 witnesses, including former FBI director James Comey, former Attorney General Loretta Lynch, former Deputy Attorney General Sally Yates, former Deputy Attorney General Rod Rosenstein, who oversaw the Russia investigation, and former FBI Deputy Director Andrew McCabe, along with FBI agents and analysts.

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Associated Press writers Mark Sherman, Alan Fram, Mary Clare Jalonick, Jonathan Lemire and Colleen Long contributed to this report.