Former FBI Director James Comey joined the chorus of Democratic critics complaining about Attorney General Bill Barr’s testimony this week that “spying did occur” against the 2016 Trump campaign, claiming he has no idea what the Justice Department leader is talking about -- and saying he “never thought of” electronic surveillance as “spying.”

Comey sought to draw a distinction between surveillance -- which was authorized against a Trump adviser -- and spying during a cybersecurity conference in California on Thursday, echoing Democratic lawmakers who have accused Barr of going too far in his Senate testimony this week.

BARR HAMMERED FOR STATING 'SPYING DID OCCUR,' DESPITE CONFIRMATION OF TRUMP TEAM SURVEILLANCE

“I have no idea what he’s talking about so it’s hard for me to comment,” Comey said.

“When I hear that kind of language used, it’s concerning because the FBI and the Department of Justice conduct court-ordered electronic surveillance,” he continued. “I have never thought of that as spying.”

He added: “If the attorney general has come to the belief that that should be called spying, wow.”

“That’s going to require a whole lot of conversations inside the Department of Justice. But I don’t know what he meant,” Comey said.

Before a Senate Appropriations subcommittee on Wednesday, Barr testified that he believes “spying did occur” on the Trump campaign, adding, “the question is whether it was adequately predicated.” Barr said he believed it was his “obligation” to review where there was any misconduct in the intelligence gathering during the origins of the Russia investigation.

But despite the backlash from Democrats over his use of the term, Barr's testimony appeared to refer to intelligence collection that already has been widely reported and confirmed.

Foreign Intelligence Surveillance Act (FISA) warrants against former Trump campaign aide Carter Page are currently the subject of a Justice Department inspector general investigation looking at potential misconduct in the issuance of those warrants. That review also reportedly is scrutinizing the role of an FBI informant who had contacts with Trump advisers in the early stages of the Russia investigation.

TRUMP DEFENDS BARR, SAYS THERE 'ABSOLUTELY' WAS SPYING AGAINST HIS CAMPAIGN

When asked about the controversy surrounding Barr’s remarks, a person familiar with his thinking denied that he was trying to fuel conspiracy theories or play to the conservative base.

“When he used the word spying, he means intelligence collecting,” the source told Fox News, also noting Barr’s history as a CIA analyst in the 1970s. “He wasn’t using it in a pejorative sense, he was using it in the classic sense.”

The Oxford Dictionary defines ‘spying’ as: “to collect information about something to use in deciding how to act,” or to “observe furtively.”

The use of the term as it applies to the FBI's surveillance in 2016 has been fiercely disputed. The New York Times, even as it reported last year on how the FBI sent an informant to speak to campaign advisers amid concerns about suspicious Russia contacts, stated that this was to "investigate" Russia ties and "not to spy."

But Barr's testimony suggests he makes no distinction between the two. He also stressed that the question for him is whether that "spying" was justified.

“I want to make sure there was no unauthorized surveillance,” Barr said.

President Trump defended the attorney general Thursday, saying that his statement was “absolutely true.”

“There was absolutely spying into my campaign,” Trump said Thursday in the Oval Office. “I’ll go a step further and say it was illegal spying. Unprecedented spying.”

Meanwhile, Comey touted Barr’s experience at the Justice Department.

“I think his career has earned him a presumption that he will be one of the rare Trump Cabinet members who will stand up for truth,” Comey said. “Language like this makes it harder, but I still think he’s entitled to that presumption and because I don’t understand what the heck he’s talking about, that’s all I can say.”

Whether proper or improper, the issue of surveillance of the Trump campaign has been widely documented.

The FISA warrants, for example, were the subject of a GOP House Intelligence Committee memo last year. That memo alleged the unverified anti-Trump dossier provided much of the basis for law enforcement officials to repeatedly secure FISA warrants against Page, though Democrats have pushed back on parts of the GOP report.

House Intelligence Committee Ranking Member Devin Nunes, R-Calif., on Thursday notified Barr of criminal referrals related to the case alleging several "potential violations" of the law.

“In late 2015, early 2016, spying began on the Trump campaign,” Nunes said on “Hannity” on Thursday. “That information leaked, that led to what they considered to be ‘legal spying’ that began, that they acknowledge they started doing at the end of July.”

He added, referring to Comey's memo-taking from high-level meetings: “You have the culmination of the ultimate spying where you have the FBI director spying on the president, taking notes, illegally leaking those notes of classified information. Why? So they can appoint a special counsel to spy on an acting president again. So there’s a lot of spying and a lot of leaking.”

Meanwhile, as part of Justice Department Inspector General Michael Horowitz’s investigation, he is reportedly probing the involvement of FBI informant Stefan Halper—whose role first emerged last year. During the 2016 campaign, Halper reportedly contacted several members of the Trump campaign, including former foreign policy adviser George Papadopoulos and Page. Halper also reportedly contacted former campaign aide Sam Clovis.

BARR REVEALS HE IS REVIEWING 'CONDUCT' OF FBI'S ORIGINAL RUSSIA PROBE

Barr also testified this week that he is conducting a Justice Department review of the “conduct” of the original Russia investigation.

“[I’m] trying to get my arms around all of the aspects of the counterintelligence investigation that was conducted in the summer of 2016,” Barr said before the House Appropriations Committee Tuesday.

Fox News' Jake Gibson and Gregg Re contributed to this report.