The Obama administration has taken the first step into a criminal investigation of the leaking of top-secret documents to major newspapers, Fox News reports.

After revelations came this week detailing the NSA's tracking of millions of Americans' emails and phone calls, "a source familiar with high-level discussions" told Fox on Saturday that a criminal report had been filed.

"We're still in early stages," White House spokesman Ben Rhodes told Fox News.

A spokesman for the Director of National Intelligence confirmed to Reuters the NSA had filed a report with the U.S. Justice Department.

From Reuters:

A criminal probe would represent another turn in the Obama administration's battle against national security leaks. This effort has been under scrutiny lately because of a Justice Department investigation that has involved searches of the phone records of Associated Press journalists and a Fox News reporter.

The investigation would likely focus on The Washington Post and The Guardian — a British paper which broke the story on June 5 that the NSA was secretly collecting millions of phone records from Verizon customers within the United States.

The Guardian later revealed top-secret information on other NSA spying programs, including PRISM — which allegedly gives the government "direct access" into prominent tech company servers such as Facebook and Google, and Boundless Informant, which counts and categorizes intelligence data and produces a worldwide "heatmap."

The Obama administration quickly denounced the leaks once they were public, calling it media "hype."

"Some of the hype that we've been hearing over the last day or so," Obama said during a press conference in San Jose, Calif. on Friday. "... Nobody's listening to the content of people's phone calls."

Director of National Intelligence James Clapper also blasted WaPo and The Guardian's publishing of the leaks, saying they lacked context.

"Over the last week we have seen reckless disclosures of intelligence community measures used to keep Americans safe," Clapper said in statement. "In a rush to publish, media outlets have not given the full context–including the extent to which these programs are overseen by all three branches of government–to these effective tools."

Glenn Greenwald, a reporter with The Guardian that broke the stories on the secret NSA programs, told Piers Morgan on Friday that the "Obama administration has been very aggressive about bullying and threatening anybody who thinks about exposing it or writing about it or even doing journalism about it."