Richard Grenell has declassified a new batch of Russia probe documents on his way out as acting director of national intelligence, leaving the decision on whether to make those files public up to newly sworn-in Director John Ratcliffe.

The documents include transcripts of phone calls that then-incoming National Security Adviser Michael Flynn and then-Russian Ambassador Sergey Kislyak had in December 2016, during the presidential transition period. Grenell said publicly last week that he was in the process of declassifying those files, after House Intelligence Committee Chairman Adam Schiff, D-Calif., asked that he do so.

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Fox News has learned that the declassification review of those transcripts is now complete, and it will be left up to Ratcliffe on whether to release them publicly.

Fox News has learned that Grenell also completed the declassification review of other documents related to the origins of the Russia probe — including one that a senior intelligence official told Fox News was “very significant in understanding how intelligence was manipulated to support launching the Russia investigation.”

The official could not provide further details on that newly declassified document, but said that it will also be up to Ratcliffe to decide whether to make it public.

The declassification comes after Grenell, who served as acting director while simultaneously serving as the U.S. ambassador to Germany, made waves with previous declassifications related to the Russia investigation, as well as other actions during his three months on the job.

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Earlier this month, Grenell cleared for release more than 6,000 pages of transcripts of interviews from the House Intelligence Committee’s long-running Russia investigation. Schiff, under pressure from Grenell and House Republicans, ultimately released the transcripts which revealed, among other things, that top Obama officials acknowledged they knew of no “empirical evidence” of a conspiracy between the Trump campaign and Russia in the 2016 election.

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Then, Grenell declassified a list of Obama-era officials who requested to unmask the identity of Flynn in intelligence reports during the presidential transition period. The roster included top-ranking figures including then-Vice President Joe Biden, then-FBI Director James Comey, then-CIA Director John Brennan, then-Director of National Intelligence James Clapper, and former President Barack Obama’s chief of staff Denis McDonough, among others.

Flynn's calls with the former Russian ambassador during the transition were picked up in surveillance and information about them was later leaked. Flynn’s case returned to the national spotlight after the DOJ moved to dismiss charges against him of lying to the FBI about those conversations, despite a guilty plea that he later sought to withdraw.

Considering those calls raised widespread concerns about Flynn, Democrats like Schiff in turn pressed Grenell for the underlying documents. The transcripts Grenell has declassified, though, are for five phone calls Flynn had with Kislyak on Dec. 29, 2016. Flynn's specific call with Kislyak from Dec. 22, 2016, which was picked up in surveillance and later leaked to the press, is in the FBI's possession, a source told Fox News, noting that it was not in Grenell's jurisdiction to declassify.

Meanwhile, last week Grenell moved to declassify an email that former National Security Adviser Susan Rice sent to herself on President Trump’s Inauguration Day, documenting a Jan. 5, 2017, Oval Office meeting with Obama and others, during which the former president provided guidance on how law enforcement needed to investigate Russian interference in the 2016 presidential race.

The declassified email revealed that Comey suggested to Obama that the National Security Council might not want to pass “sensitive information related to Russia” to Flynn, due to the fact that he had been “speaking frequently” with the Russian ambassador.

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Grenell also declassified more than three dozen previously redacted footnotes from the Justice Department inspector general’s report into intelligence community failures during the Russia investigation.

“Richard Grenell brought unmatched energy and transparency to ODNI during his tenure there,” a senior administration official told Fox News. “He took seriously the rule that classification must not be used to hide potential misconduct or to save the government from embarrassment.”

The official added that Grenell “made strides to depoliticize intelligence and towards rebuilding the American peoples’ trust in the IC.”

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But Democrats criticized Grenell for being a staunch Trump loyalist, and accused him of carrying out duties as acting intelligence director in the president’s interest.

Schiff said in a recent letter to Grenell that his declassification of the list of Obama administration officials is "without precedent" and "corrupt."

"It was a transparent political act — in an election year and during a pandemic, no less — in which you used the authorities of your position to insinuate wrongdoing by officials who acted appropriately in requesting the identity of masked U.S. persons to better understand foreign intelligence reports," Schiff wrote. "This is inconsistent with the oath and obligations of an acting Director of National Intelligence."

However, aside from his declassification of documents related to the Russia probe, Grenell made other big moves within ODNI during his three-month tenure.

A senior intelligence official told Fox News that during his time at ODNI, Grenell appointed the first female to lead the National Counterterrorism Center, Lora Shiao; established an intelligence community-wide working group to support a policy for the decriminalization of homosexuality in the 69 countries where being LGBT is a punishable offense; finalized and released the National Intelligence Estimate on the future of ISIS through 2021; and engaged foreign liaison partners to form a working group to increase intelligence sharing with key allies on Hezbollah.

The official also told Fox News that Grenell directed the intelligence community to change the way it protects the identities of U.S. citizens contained within intelligence reporting, urging consistency to the process and ensuring the “greater privacy” of U.S. citizens.

Earlier this month, Grenell also announced that the intelligence community would lead new election security threat briefings for presidential candidates, their campaigns and major political parties ahead of the 2020 election. The decision was not made unilaterally, but was “coordinated and approved” by all agencies involved, including the FBI, Department of Homeland Security and other agencies inside the intelligence community.

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Another senior intelligence official said that Grenell “set a good precedent for John Ratcliffe to follow, and if the new DNI continues in this mold, the country will be stronger for it.”

Ratcliffe was sworn-in as director of national intelligence on Tuesday by Grenell at ODNI, after having been confirmed to the post by the Senate last week.

During his confirmation hearing earlier this month, Ratcliffe, until recently a Republican member of Congress representing a Texas district, pledged to senators that he’d deliver intelligence information without bias if confirmed for the job. Ratcliffe, who was one of Trump’s fiercest allies during impeachment, said he had the experience to be an independent leader of the nation’s 17 intelligence agencies, given his past work as a federal prosecutor.

“The best job I ever had was to be the United States attorney and what I loved… it was an apolitical position,” Ratcliffe told the Senate Intelligence Committee earlier this month. “I stood up always to represent the United States of America. Never one party or another. And I very much view that as this role for the DNI.”