Former FBI Director Robert Mueller (front), the special counsel probing Russian interference in the 2016 US election, leaves the Capitol building after meeting with the Senate Judiciary Committee on Capitol Hill in Washington D.C., the United States, on June 21, 2017.(Photo: Xinhua)

 
The US Department of Justice's watchdog released a report on Monday examining the origins of the FBI's investigation into possible ties between US President Donald Trump's campaign and alleged Russian interference in the 2016 US presidential election.

The 434-page report, issued by the department's Inspector General Michael Horowitz, found several procedural errors but overall no "political bias" by the Federal Bureau of Investigation (FBI) in launching the investigation.

The conclusions were based on over 1 million documents from the department and the FBI and interviews with over 100 witnesses, Horowitz said.

Horowitz will testify before the Senate Judiciary Committee on Wednesday about his report.

FBI Director Christopher Wray responded in a statement that he accepted the report's findings and acknowledged that "certain FBI personnel" had failed to comply with the FBI's policies and standards of conduct, and the agency "embraces the need for thoughtful, meaningful remedial action."

Senate Minority Leader Chuck Schumer tweeted the report "makes clear that the predicate for the FBI's investigation was valid & without political bias."

The report "shows there is no basis for President Trump's absurd claim that the investigation into his campaign was a hoax or a conspiracy against him," Schumer wrote.

US Attorney General William Barr, in contrast, disagreed with the report's findings.

"The Inspector General's report now makes clear that the FBI launched an intrusive investigation of a US presidential campaign on the thinnest of suspicions that, in my view, were insufficient to justify the steps taken," Barr said.

US Connecticut State Attorney John Durham, who is leading a separate review on the FBI's investigation, also questioned the report's conclusions.

"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," Durham said in a statement.

Durham's probe is a criminal investigation, which gives him the authority to issue subpoenas to witnesses and documents, as well as to impanel a grand jury.

Speaking to reporters at the White House on Monday, Trump said he has been briefed on Horowitz's report.

"The details of the report are far worse than anything I would have imagined," Trump said, adding he was looking forward to the release of the Durham report.

The FBI began the Russia probe in July 2016, which former special counsel Robert Mueller took over in May 2017 as Trump fired the agency's director James Comey.

Mueller, who concluded his investigation in March, wrote in a report that there was no evidence that Trump's political campaign conspired with Moscow during the 2016 US presidential election. However, the report did not conclude whether the president had obstructed justice.