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(CNN) —  

Attorney General William Barr suggested to lawmakers Wednesday that Donald Trump’s presidential campaign was spied on, saying he will be looking into the “genesis” of the FBI’s counterintelligence investigation that began in 2016 of potential ties between the campaign and the Russian government.

“I think spying on a political campaign is a big deal,” Barr said, echoing some of the more inflammatory claims lobbed by the President for months, but declining to elaborate on his concerns. “I think spying did occur.”

He did not provide evidence for his claims.

The news will likely be viewed as a welcome development to the President, who has regularly called for an investigation and, as recently as last week, told reporters more should be done to examine the origins of the Russia probe.

It will also likely raise concerns of politicization of the Department of Justice’s work at an already tense time, as Democrats worry that Barr is bending to the President’s demands and have called on Barr to release an unredacted version of the special counsel’s confidential report on the Russia investigation to Congress.

Congressional Democrats fumed Wednesday over Barr’s statements, accusing the attorney general of mischaracterizing the FBI’s counterintelligence investigation in an effort to please Trump.

“I’m amazed that the AG would make that kind of statement, I think it’s in many ways disrespectful to the men and women who work in the DOJ, and it shows, I think, either a lack of understanding or willful ignorance on what goes into a counterintelligence investigation,” Virginia Sen. Mark Warner, the top Democrat on the Senate Intelligence Committee, told CNN.

“These comments directly contradict what DOJ previously told us,” tweeted House Judiciary Chairman Jerry Nadler, who authorized the subpoena for the Mueller report. “I’ve asked DOJ to brief us immediately.”

Former Director of National Intelligence James Clapper, who served in the Obama administration, told CNN’s Anderson Cooper Wednesday night that Barr’s statement was “both stunning and scary.”

Yet, according to a source familiar with his thinking, when Barr spoke of “spying” on the Trump campaign, he meant it in the “classic sense” of intelligence collection. He doesn’t view the term as “pejorative,” the source said.

When asked if Barr used the word “spy” to throw a bit of red meat toward conspiracy theorists who voiced concerns over surveillance tactics, the person said flatly: “no.” The source emphasized repeatedly that Barr is focused on whether there was proper “predication” for any surveillance – something he stated publicly at Wednesday’s hearing.

Barr’s own review of the FBI’s counterintelligence work, first reported by Bloomberg and confirmed by a US official to CNN, was briefly touched on during his House appropriations hearing, but the attorney general went further during Wednesday’s Senate appropriations hearing explaining his reasoning.

“For the same reason we’re worried about foreign influence in elections, I think spying on a political campaign is a big deal,” Barr said. I’m not suggesting those rules were violated but I think it’s important to look at… . I think it’s my obligation.”

He added that he’s not launching a full blown investigation into the FBI and and does not view it as a problem that is “endemic” to the FBI, but has in mind some colleagues to help him “pull all this information together, and letting me know if there are some areas that should be looked at.”

Trump said Wednesday morning that Barr was doing a “great job” and “getting started on going back to the origins on where exactly this all started because it was an illegal witch hunt.”

“This was an attempted coup, this was an attempted takedown of a president,” Trump said.

The US official told CNN that Barr’s review is separate from the ongoing work being conducted by the Justice Department’s internal watchdog, Inspector General Michael Horowitz, but could not detail its precise scope nor explain how the work of US Attorney John Huber, who was also tasked with investigating surveillance matters, factors in at this stage. Barr did not elaborate further.

In March 2018, amid calls by Republican lawmakers for a second special counsel to investigate how the Russia investigation began, then-Attorney General Jeff Sessions revealed that Huber was looking into allegations that the FBI abused its powers in surveilling former Trump foreign policy aide Carter Page among other issues.

At the same time, Horowitz’s office confirmed it would “review information that was known to the DOJ and the FBI at the time the applications were filed from or about an alleged FBI confidential source” and “review the DOJ’s and FBI’s relationship and communications with the alleged source as they relate to the (Foreign Intelligence Surveillance Court) applications.”

Yet those efforts by Sessions to appease Trump and his allies on Capitol Hill appeared less than sufficient at the time.

Trump claimed on Twitter that the inspector general was the wrong person to probe possible FISA abuse, calling the move “disgraceful.”

Barr said Tuesday he expected Horowitz’s review will be completed in “May or June.”

This story has been updated with additional developments Wednesday.

CNN’s Manu Raju and Jeremy Herb contributed to this report.