Congressional intelligence committees vow to investigate ‘alarming and unacceptable’ leaks

President Barack Obama's administration faced escalating pressure Wednesday over a wave of news reports detailing sensitive national security operations, as the leaders of Congress's intelligence committees vowed to investigate whether vital secrets were improperly leaked.

In a rare and sharply worded joint statement, Democratic Senator Dianne Feinstein and Republican Senator Saxby Chambliss as well as Republican Representative Mike Rogers and Democratic Representative C.A. Dutch Ruppersberger warned that each disclosure "threatens imminent and irreparable damage to our national security."

"The accelerating pace of such disclosures, the sensitivity of the matters in question, and the harm caused to our national security interests is alarming and unacceptable," wrote the lawmakers, who are the chair and ranking member of the Senate and House Intelligence Committees.

The lawmakers said they would "quickly" take up legislation to tighten security around classified information.

"We also intend to press for the executive branch to take tangible and demonstrable steps to detect and deter intelligence leaks, and to fully, fairly, and impartially investigate the disclosures that have already taken place," they said.

At issue, notably, were a pair of New York Times articles--one detailing how Obama ordered a cyberattack on Iran's nuclear program, another describing the president's central role in deciding when to target individuals for assassination.

Earlier, the White House hit back hard at Republican Senator John McCain's charge that the leaks sprang from "the highest levels of the White House" to help President Barack Obama's political fortunes.

"Any suggestion that this Administration has authorized intentional leaks of classified information for political gain is grossly irresponsible," spokesman Jay Carney told reporters aboard Air Force One.

Carney's comments came after McCain charged Tuesday on the Senate floor that the leaks were part of an "administration effort to paint a portrait of President Obama as a strong leader on national security issues."

McCain repeated that allegation Wednesday on CBS's "This Morning."

"This is the most highly classified information and has now been leaked by the administration at the highest levels of the White House," McCain said.

"This administration takes all appropriate and necessary steps to prevent leaks of classified information or sensitive information that could risk ongoing counter-terrorism or intelligence operations," Carney said.

The Intelligence Committee leaders made clear that the White House approach was not sufficient. "The problem of leaks of classified information is not new, and efforts in the past to address it have not worked. We believe that significant changes are needed, in legislation, in the culture of the agencies that deal with classified information, in punishing leaks, and in the level of leadership across the government to make clear that these types of disclosures will not stand," they said.

The issue also flared up at a Senate Judiciary Committee hearing, when lawmakers questioned Deputy Attorney General James Cole about the leaks.

John Cornyn, a Republican senator from Texas, asked Cole whether the Justice Department should appoint a special prosecutor to look into the leaks. "I don't believe that it would be necessary in this case, no," Cole replied.

"It is puzzling that the administration would be opposed to an independent investigation of what appears to be a serious breach of national security," Cornyn said later in a statement emailed to Yahoo News.

At the hearing, Democratic Senator Patrick Leahy, the committee's chairman, said reading the New York Times reports on secret projects left him "fuming."

"I have not had a briefing yet to determine whether what was in there was accurate or not, so I'm not saying what it was, but if it was, it should not be in a newspaper," he said.

And Democratic Senator Sheldon Whitehouse raised the possibility that the leaks could be coming from executive branch officials he identified as "declassifiers" empowered to disclose secrets merely by discussing them. "As they utter classifid information it becomes declassified because they have uttered it," he said.

Feinstein announced Tuesday that she had sent Obama "a classified letter" outlining her concerns.