WASHINGTON -- With pressure mounting on the administration over its detainee policies, Republican House and Senate leaders today sought a Congressional probe into who leaked information on the existence of CIA-run secret prisons abroad to the Washington Post.

Senate Majority Leader Bill Frist (R-Tenn.) and House Speaker J. Dennis Hastert (R-Ill.) circulated a letter asking the intelligence committees to "immediately initiate a joint investigation into the possible release of classified information to the media," about the existence of the prisons.

"As you know, if accurate, such an egregious disclosure could have long-term and far-reaching damaging and dangerous consequences," the pair said in their letter to Rep. Peter Hoekstra (R-Mich.), chairman of the House Intelligence Committee, and Sen. Pat Roberts (R-Kan.), chairman of the Senate Intelligence Committee.

The request came as Democrats continued to demand an independent inquiry into allegations of detainee abuse and into the administration's handling of pre-war intelligence, and Sen. John McCain (R-Ariz.) continued his fight to issue clear instructions to U.S. military and intelligence personnel banning cruel and inhumane treatment of prisoners.

The Senate has passed a McCain-sponsored amendment barring torture of detainees and setting standards for their treatment. The administration opposes the restrictions and has threatened to veto the $440 billion defense bill to which it is attached. The House has not voted on the measure.

Responding to news of the request by congressional leaders for a probe into the source of the Post's information, White House press secretary Scott McClellan said it was a serious matter.

"It ought to be taken seriously," McClellan said. "But this is a congressional prerogative and it was a decision that was made by those leaders and that's the way I would describe it."

On Nov. 2, the Post revealed the existence of a network of clandestine prisons in Eastern Europe where it said the CIA was holding suspected terrorists. The administration has neither confirmed nor denied the report, but its publication intensified the debate on Capitol Hill about the administration's detainee policies.

Late this afternoon, a senior Republican aide on the Senate Intelligence Committee said the panel had not yet received Frist's and Hastert's letter. The aide, who requested anonymity because of the political sensitivity of the issue, said he could not recall an instance in which the committee investigated an alleged leak of classified information, except when there was suspicion that someone on the panel's staff had been involved.

"We will work with the leadership," if Frist's office wants a congressional probe, the aide said. But he cautioned that leak investigations ordinarily were carried out by the Justice Department, and that the committee generally avoided encroaching on criminal probes.

"If the Justice Dept. gets engaged, it becomes very problematic to cross paths with them," the aide said.

Democratic congressional leaders welcomed the call for an investigation, but said it should be broader than the possible leak of classified information about the prison system.

In a statement, Senate Minority Leader Harry Reid (D-Nev.) said that "leaking is unacceptable." But, he said, "while Republicans have been quick to call for an investigation of this matter, they have repeatedly and regularly resisted any real oversight of this administration's flawed policies."

The minority leader said he hoped the majority's "newfound zeal for investigations," will mean they will also push for a probe into "how this administration used and misused intelligence as it made its case for war in Iraq."

House Minority Leader Nancy Pelosi (D-San Francisco) said that "if Speaker Hastert and Majority Leader Frist are finally ready to join Democrats' demands for an investigation of possible abuses of classified information, they must direct the House and Senate Intelligence Committee to investigate all aspects of that issue."

At least one Senate Republican agreed.

Asked whether he believed there should be a probe of the possible leaking of classified information on the existence of the prisons, or of the existence of the prisons themselves, Sen. Lindsey Graham of South Carolina, a former military lawyer, rolled his eyes and replied: "How about both? I'd like to know why we've got secret prisons and what oversight precautions we have."

Graham said it was "imperative we regain the moral high ground and having secret prisons come out in the Washington Post is not a good way to regain it."

Another Republican, Sen. Trent Lott of Mississippi, said it may have been Republican senators who leaked the information to the Post. Lott told reporters that the existence of the secret prison system was discussed last week during the Republican policy luncheon, held on Capitol Hill the day before the Post story appeared.

"Information that was said in there, given out in there, did get into the newspaper," Lott said.

Asked whether he believed it was Republicans who had breached security, Lott said: "I don't know where else it came from...it looked to me that at least one of those reports came right out of that room."

In their letter, Frist and Hastert said the committees should determine whether the information given to the Post was accurate, who leaked it and "what is the actual and potential damage done to the national security of the United States and our partners in the global war on terror."

The leaders said they would "consider other changes to this mandate based on your recommendations." They said that "the leaking of classified information by employees of the United States government appears to have increased in recent years, establishing a dangerous trend that, if not addressed swiftly and firmly, likely will worsen."

Earlier this month, I. Lewis Libby, Vice President Dick Cheney's chief of staff, was indicted on five counts of perjury, obstruction of justice and giving false statements in connection with the leak to reporters of the name of a CIA operative, Valerie Plame. Libby, who has since resigned, has pleaded not guilty to those charges.

Commentary:
Republicans couldn't wait to demand hearing and an investigation into a leak that once again tarnished their angelic reputation. But, we quickly learn it was a fellow GOP senator who leaked the prison info. to the press. How does the Washington Post report this devolvement? They ignore all of Lott's quotes.

At a minium, the Washington Post is part of a GOP coverup or their completely incompetent. Every liberal blog is running with this story but the Washington Post doesn't know about Lott's statements? Washington Post = Coverup.

If necessary we'll see how many other major papers, networks and cable channels ignore Lott's statements. The pro war media still doesn't get it; they should report as if they're in before a jury; "the truth, the whole truth and nothing but the truth."