The Justice Department is launching a review of decisions made by its counterintelligence division and the FBI in probing Russian interference in the 2016 presidential election and potential infiltration of the Trump campaign, Attorney General William Barr confirmed Wednesday.

"I am going to be reviewing both the genesis and the conduct of intelligence activities directed against – at the Trump campaign during 2016," Barr said during a Senate appropriations subcommittee hearing on the Justice Department's budget request for fiscal 2020.

Barr's plan for review, first revealed by Bloomberg late Tuesday, is reportedly focusing on whether bias against President Donald Trump influenced the investigation. Barr in his testimony the following day offered few details on the probe, but he seemed to confirm that he agrees with at least some allegations by conservative politicians and pundits that law enforcement and intelligence agencies engaged in "spying" on the Trump campaign.

"I think spying did occur," Barr testified. "But the question is whether it was predicated, adequately predicated, and I'm not suggesting it wasn't adequately predicated, but I think I need to explore that. I think it's my obligation – Congress is usually very concerned about intelligence agencies and law enforcement agencies staying in their proper lane, and I want to make sure that happened."

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The Justice Department's Office of Inspector General, which serves as the agency's watchdog, has launched its own probes into elements of the Russia investigations, including whether certain foreign surveillance warrants were properly pursued and issued, and the conduct of several investigators involved in the probe.

Barr's review would draw from those findings, as well as materials gathered by the DOJ in investigating Russian election interference and by various congressional committees in their own Russia probes.

The attorney general signaled that he is focused on previous leaders at the FBI, suggesting that ousted former director James Comey and fired deputy director Andrew McCabe, who each have faced withering attacks from conservative lawmakers, will face yet further scrutiny.

"This is not launching an investigation of the FBI. Frankly, to the extent that there were any issues at the FBI, I do not view it as a problem that's endemic to the FBI," Barr testified. "I think there was probably a failure among a group of leaders there at the upper echelon."