WASHINGTON – Attorney General Jeff Sessions announced a broad crackdown on unauthorized disclosures of classified information Friday, warning both would-be leakers and the media as he demanded that the "culture of leaking must stop."

Referring to an "explosion'' of leaks since January, Sessions said the Justice Department has “more than tripled" the number of active leak investigations compared to the number pending at the end of the Obama administration.

Justice has already received nearly as many criminal referrals involving unauthorized disclosures of classified information than in the previous three years combined, Sessions said.

"I have this warning for would-be leakers: Don't do it," Sessions said. "I strongly agree with the president and condemn in the strongest terms the staggering number of leaks," he said.

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At the same time, Sessions offered an ominous warning to the press, saying that prosecutors have launched a review of Justice policy related to subpoenas issued to media organizations in criminal investigations.

"We respect the important role that the press has and we give them respect, but it is not unlimited," Sessions said. "They cannot place lives at risk with impunity."

Sessions' remarks threatened a break with the Obama Justice Department policy, which asserted that reporters would not be targeted.

Former Attorney General Eric Holder, taking fire for aggressive investigative tactics taken against journalists, pledged in 2013 that he would "not prosecute any reporter'' for doing their jobs.

The Trump Justice Department, however, has offered no such blanket protections, as Sessions also announced the creation of a new counter-intelligence unit within the FBI that would focus exclusively on leaks of classified material to the press and others.

In a briefing following Friday's announcement, Deputy Attorney General Rod Rosenstein declined to comment on whether reporters would be prosecuted under any new policy. But Rosenstein did commit to consulting with media organizations before any new policy is promulgated.

A media advisory group was formed during the Obama administration in wake of a series actions taken against reporters and news organizations in pursuit of leak investigations.

Sessions and Director of National Intelligence Dan Coats, who also condemned the unauthorized disclosures, appeared together a day after The Washington Post published complete transcripts of Trump's first calls with Mexican President Enrique Peña Nieto and Australian Prime Minister Malcolm Turnbull.

"No government can be effective when its leaders cannot discuss sensitive matters in confidence or to talk freely in confidence with foreign leaders,'' the attorney general said.

Coats, meanwhile, characterized the steady stream of disclosures during the last several years as "the worst compromise of classified information in the nation's history.''

"Let me be absolutely clear,'' Coats said, "these disclosures have resulted in a major threat to our national security.''

Coats said the information has given adversaries an intelligence advantage while exacting monetary costs to "compensate for blown (intelligence) programs.''

The joint Justice and DNI announcement comes just after President Trump spent much of past 10 days publicly deriding his attorney general and calling on Sessions to be much tougher on leaks from intelligence agencies, which have proved particularly damaging to the White House.

But Sessions, who last week described Trump's criticisms as "hurtful,'' said Friday that he and the president were in lock-step on fighting leaks.

"Just yesterday, we saw reports in the media about conversations the president had with foreign leaders,'' the attorney general said, referring to The Post report. "No one is entitled to surreptitiously fight their battles in the media by revealing sensitive government information.''

Trump’s anger over the disclosure of sensitive and classified information has been a consistent theme of his young administration and even before his inauguration.

Less than two weeks before taking office, Trump unleashed a vehement attack against U.S. intelligence agencies, accusing them of leaking the contents of a lurid, unsubstantiated dossier compiled on Trump.

Intelligence officials denied leaking the document, which had been widely circulated among lawmakers and journalists before its publication.

Yet, hours after the dossier’s public disclosure Jan. 10, Trump lashed out at the intelligence agencies, blaming them and comparing their alleged actions to the gestapo tactics of “Nazi Germany.’’

The president’s public criticism stunned intelligence officials, prompting then-Director of National Intelligence James Clapper to call the president-elect in defense of the agencies.

The sting of Trump’s remarks still lingers.

Last month, former CIA Director John Brennan called Trump’s “disparagement’’ of the intelligence community as “disgraceful.’’

Asked whether the White House, having repeatedly expressed concerns about leaks, pushed the Justice Department to take action, Rosenstein declined to comment. Sessions and Coats did not take questions following their remarks.

The action Friday prompted an outpouring of support from conservatives, who lauded Sessions despite Trump's recent criticisms.

“Attorney General Sessions has proven to be one of President Trump’s most loyal and effective Cabinet secretaries,'' said president and cofounder of the Tea Party Patriots, Jenny Beth Martin. "Today’s announcement of an investigation into damaging leaks that have harmed our national security is just the latest example of how Sessions is proving to be an effective attorney general.''

Free speech and civil rights advocates, however, described the administration actions as akin to a threat against the press.

“Every American should be concerned about the Trump administration’s threat to step up its efforts against whistleblowers and journalists,'' said Ben Wizner, director of the ACLU's Speech, Privacy and Technology Project.

"A crackdown on leaks is a crackdown on the free press and on democracy as a whole.''