President Trump on Monday said it was time to “investigate the investigators,” doubling down on Attorney General Bill Barr’s summary of Special Counsel Robert Mueller’s findings in the Russia investigation.

“Mueller, and the A.G. based on Mueller findings (and great intelligence), have already ruled No Collusion, No Obstruction. These were crimes committed by Crooked Hillary, the DNC, Dirty Cops and others! INVESTIGATE THE INVESTIGATORS!” Trump tweeted early Monday.

COMEY SCOFFS AT BARR TESTIMONY, CLAIMS 'SURVEILLANCE' IS NOT 'SPYING'

The president’s tweet comes following a week of mounting scrutiny on the attorney general for his testimony that “spying did occur” on the Trump campaign during the 2016 presidential election.

Democrats blasted Barr, and accused him of “peddling conspiracy theories.”

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.

A person familiar with Barr’s thinking denied that the attorney general was trying to fuel conspiracy theories or play to the conservative base.

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

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

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.”

Barr’s testimony, though, suggested 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 testified.

The president has defended the attorney general repeatedly since the comments were made, saying that they were “absolutely true.”

“There was absolutely spying into my campaign,” Trump said last week. “I’ll go a step further and say it was illegal spying. Unprecedented spying.”

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.

Meanwhile, Barr announced last 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 last week.

That review comes amid Justice Department Inspector General Michael Horowitz’s investigation, where 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 Page, and former foreign policy adviser George Papadopoulos. Halper also reportedly contacted former campaign aide Sam Clovis.

Republicans on the Senate Judiciary Committee, led by Chairman Lindsey Graham, R-S.C., also vowed to lead an investigation into "the other side" following the release of Barr's summary.

During his testimony, Barr promised to release the full Mueller report “within a week,” maintaining his original promise to have the report to Congress and the public, with redactions, by mid-April. It is unclear when the report will be released.

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

Last month, Mueller transmitted his more than 300-page report to the Justice Department for review. Barr’s summary stated that the special counsel found no evidence of collusion between members of the Trump campaign and the Russians during the 2016 election.

Mueller also was reviewing possible obstruction of justice on the part of the president, but did not come to a conclusion on the topic, and instead, leaving it to Barr.

Barr and Deputy Attorney General Rod Rosenstein said that the evidence from the case was “not sufficient to establish that the president committed an obstruction-of-justice offense.”