Whoever leaked the transcripts of President Trump’s phone calls with foreign leaders to the press likely committed a crime, former prosecutors said Thursday – as lawmakers called for rooting out the culprit.

“The unauthorized release of these documents to the press is a crime,” Joe diGenova, the former U.S. attorney for the District of Columbia, told Fox News. “The series of acts involving release of notes of the president’s conversations with foreign leaders, and these transcripts, are a serious threat to national security.”

Based on the leaked documents, The Washington Post reported new details Thursday about Trump's tense phone calls in late January with Mexican President Enrique Peña Nieto and Australian Prime Minister Malcolm Turnbull. In the former, Trump reportedly told the Mexican leader to stop publicly saying his government would not pay for a border wall.

The newspaper said the transcripts had notes indicating they had been classified by the chief of staff on the National Security Council. The Post said it obtained full transcripts, which were “produced by White House staff” and based on records kept by White House note-takers.

“There is a federal statute that makes it a crime, a federal crime, to disseminate classified information to an unauthorized person,” Doug Burns, a former federal prosecutor in New York, said in a phone interview.

TRANSCRIPTS OF TRUMP'S FOREIGN LEADER PHONE CALLS EMERGE

While some details of those calls already had emerged in February, the release of the transcripts marks a much bigger blow to a White House trying to crack down on leaks. The report incidentally was published as top figures in the Trump administration are preparing to go before the public on Friday in a show of force to demonstrate their commitment to rooting out leakers of classified information.

Attorney General Jeff Sessions, Director of National Intelligence Dan Coats, Deputy Attorney General Rod Rosenstein and National Counterintelligence and Security Center Director William Evanina are all expected to brief the public at Justice Department headquarters.

It's unclear whether the Post leak might be investigated by the DOJ.

To prosecute someone for this, Burns said there are “certain elements that obviously have to be shown.” He said “there can be dust-ups over that,” citing the investigation into former Secretary of State Hillary Clinton’s emails and the decision not to prosecute.

Those considerations include the markings and history of the document and its exact classification. If classified, prosecutors would look to see if it was disseminated to an unauthorized person in a manner that negatively affects the interests of the United States.

“If all of those things can be proven, people can very definitely be in harm's way for criminal exposure,” Burns said. “No question.”

Speaking of the transcripts of Trump's phone calls, diGenova, who prosecuted espionage cases, said these documents are “generally classified at secret and above.”

Claiming the leaks imperil the ability of the U.S. government to conduct foreign policy, diGenova called on the attorney general to institute a federal criminal grand jury to find the leakers. He also said the phone records of the reporters and editors of The Washington Post should be subpoenaed, something the journalists would surely protest.

On Capitol Hill, Utah Republican Sen. Mike Lee said Thursday there should be criminal prosecution for leaking classified information.

“Whoever leaked these needs to be found out and needs to be reprimanded, needs to be fired,” Lee told Fox News' "America's News HQ." “This is unacceptable and should never happen.”

Lee, who practiced law before being elected to the Senate in 2010, said such a leak “is a felony, a very serious federal felony offense.”

“Doing something like this could not only and should not only result in termination but also criminal prosecution to the extent there’s classified information involved,” he said.

Friday’s announcement at the Department of Justice may provide more of an overview of what the DOJ hopes to accomplish rather than specific prosecutions at this stage, Fox News is told.

Last week, the president, lashing out against in his attorney general in public, criticized Sessions for not doing enough to find the leakers.

“I want the attorney general to be much tougher on the leaks from intelligence agencies,” Trump said in the Rose Garden on July 25.

Sessions himself, speaking to Fox News’ Tucker Carlson last week, admitted he has not been satisfied with the efforts to investigate leaks, which have repeatedly hampered the president since his inauguration.

"I have not been happy with the past prosecutions and investigations of criminal leaks," Sessions said.

Even some critics of the president have spoken out against the leaks, saying such efforts harm foreign policy efforts.

“Leaking the transcript of a presidential call to a foreign leader is unprecedented, shocking, and dangerous,” David Frum wrote in the Atlantic on Thursday. “It is vitally important that a president be able to speak confidentially—and perhaps even more important that foreign leaders understand that they can reply in confidence.”

Sen. Mark Warner, D-Va., top Democrat on the Senate Intelligence Committee, also told The Daily Beast the leak is "absolutely" troubling and should be investigated by Congress.

Fox News’ Judson Berger contributed to this report.