US Attorney General Eric Holder appointed two prosecutors to lead a criminal investigation into recent instances of possible unauthorised disclosures of classified information. The "highly-respected and experienced prosecutors will be directing separate investigations currently being conducted by the Federal Bureau of Investigation," Holder said in a statement.
"I have notified members of the Congress and plan to provide more information, as appropriate, to members of the judiciary and intelligence committees," he said. "The unauthorised disclosure of classified information can compromise the security of this country and all Americans, and it will not be tolerated," said Holder.
The two attorneys appointed to probe the leaks are Ronald C Machen Jr and Rod J Rosenstein. The move came after days of strong criticism from lawmakers and allegations from Republicans that the leaks were done purposefully to benefit, but those harmed the national security interest.
Earlier in the day, US President Barack Obama refuted reports that these were purposefully leaked by the White House to help his reelection campaign.
"The notion that my White House would purposely release classified national security information is offensive. It's wrong, and people, I think, need to have a better sense of how I approach this office and how the people around me here approach this office," Obama said.
In the recent past, several news reports have appeared on the front pages of leading US dailies on various issues, including the one that he personally supervises terrorist kill lists and that he ordered cyber-attacks on the Iranian nuclear programme.
At a White House news conference, Obama said he has "zero tolerance" against such leaks. "Now, we have mechanisms in place where if we can root out folks who have leaked, they will suffer consequences. In some cases, these are criminal acts when they release information like this. And we will conduct thorough investigations, as we have in the past," he said.
"We're dealing with issues that can touch on the safety and security of the American people, our families, or our military personnel, or our allies. And so we don't play with that. And it is a source of consistent frustration, not just for my administration but for previous administrations, when this stuff happens," he said.
"We will continue to let everybody know in government, or after they leave government, that they have certain obligations that they should carry out. But as I think has been indicated from these articles, whether or not the information they've received is true, the writers of these articles have all stated unequivocally that they didn't come from this White House. And that's not how we operate," Obama said.
In a statement, two top US Senators Lindsey Graham and John McCain alleged that there have been orchestrated leaks of classified information involving some of the most sensitive counter-terrorism operations.
"These breaches of national security have compromised operations, strained relationships with allies, and put lives at risk. It is imperative that an independent investigation be conducted where the results could be accepted with a high degree of confidence and without a hint of political considerations," they said.
Graham and McCain said this investigation involves some of the most serious breaches of national security in recent memory and any investigation must be done in a manner free and clear of political considerations.
"The recent decision of the attorney general falls far short of what is needed and is not an adequate substitute for an outside special counsel," they said.