WASHINGTON » U.S. forces and diplomatic missions overseas braced Monday for the release of the public version of a long-awaited Senate Intelligence Committee report into the CIA’s use of torture after a U.S. intelligence community warning of a "heightened potential" for a "violent response," U.S. officials said.

The report’s roughly 500-page executive summary, which the White House said would be unveiled Tuesday, excoriates the CIA, concluding that it didn’t gain significant intelligence or the cooperation of detainees by using the harsh interrogation methods, had wrongly subjected some people to the procedures and misled the White House and Congress about the results.

The Democrat-led committee’s conclusions, which were obtained in April by McClatchy, are being fiercely disputed by current and former CIA officials, former President George W. Bush and senior officials of his administration, and some lawmakers, mostly Republicans. They contend that the program produced valuable information that disrupted terror plots and led to the capture of key al-Qaida operatives.

"We did what we were asked to do, we did what we were assured was legal. And we know our actions were effective," Jose Rodriguez, the former senior CIA official who oversaw the program, wrote in an op-ed piece published Sunday in The Washington Post.

The committee voted in December 2012 to approve a final draft of a 6,300-page classified version of the report and an executive summary, findings and conclusions for release to the public. But the release was delayed by an uproar over CIA monitoring of the committee staff’s computers and a battle over administration demands to black out information that it contended could reveal the identities of undercover CIA officers and anger foreign governments.

The $40 million report, McClatchy revealed in October, sidesteps an assessment of the responsibility for abuses of Bush, who authorized the program, former Vice President Dick Cheney, a key advocate who closely monitored the interrogations, and other senior officials who played significant roles.

Even so, the executive summary of 20 case studies examined by the committee was expected to reveal new chilling details of the treatment of detainees that the panel’s chairwoman, Sen. Dianne Feinstein, D-Calif., described as "un-American" and "brutal."

"Everybody needs to know what happened and why it happened and how we never have to let this happen again," said Sen. John McCain, R-Ariz., a former Navy pilot who was captured and tortured by the North Vietnamese and a fierce critic of the CIA program.

Following the Sept. 11, 2001, attacks, Bush authorized the CIA to use 10 harsh interrogation techniques on suspected al-Qaida terrorists who were abducted overseas and detained in secret "black site" prisons in foreign countries.

The methods, which were used from 2001 until 2006, included wall-slamming, confinement in a box, stress positions, sleep deprivation and waterboarding, a procedure that produces a sensation akin to drowning and is known to have been used on three detainees, including Khalid Sheikh Mohammed, the alleged mastermind of the 9/11 attacks.

President Barack Obama, Attorney General Eric Holder and other senior current and former U.S. officials, other governments and human rights organizations have denounced the techniques as torture.

Minority Republicans on the Senate Intelligence Committee and the CIA were expected to release separate rebuttals rejecting the findings shortly after the report is made public.

Sen. Susan Collins, R-Maine, said she would be releasing her own "additional views" critical of the way the investigation was conducted, including a decision not to interview CIA and other officials who were involved in the so-called Rendition, Detention and Interrogation Program.

"Although I voted for the release of the report and I believe the techniques are abhorrent and contrary to American values, I remain disappointed in the way the report and investigation were conducted," Collins told McClatchy.

In a recent assessment of the possible impact of the release of the executive summary, the U.S. intelligence community warned Congress and government departments that there could be a violent backlash, said a senior U.S. intelligence official.

"The IC (intelligence community) has an obligation and solemn duty to warn of the heightened potential that the release could stimulate a violent response," said the senior U.S. intelligence official, who requested anonymity because the actual assessment is classified. "We have shared the information with Congress and with our interagency partners for preparation and planning purposes."

The Obama administration has been preparing for the executive summary’s release for months amid concerns for the security of U.S. facilities overseas, said White House spokesman Josh Earnest, who revealed that the document would be made public Tuesday.

"The administration has taken the prudent steps to ensure that the proper security precautions are in place at U.S. facilities around the globe," said Earnest. "But that said … the administration strongly supports the release."

At the State Department, spokeswoman Jen Psaki said that the chiefs of all U.S. diplomatic missions were asked to review their security postures, as they did several months ago following rumors then that the executive summary would be released.

Every diplomatic post has conducted a review "given the range of possible reactions overseas," said Psaki, who denied reports that U.S. facilities had been placed on high alert. "There wasn’t a new worldwide caution or anything like that issued."

Army Col. Steve Warren, a Pentagon spokesman, said that the Defense Department was concerned that the executive summary’s publication "could cause unrest" and that U.S. commanders around the world were alerted to the pending release.

Commanders in the Middle East and Africa stepped up security, including putting on heightened alert Marine crisis response teams, the Pentagon said.

Some experts, however, downplayed the potential for serious violence, saying that militants determined to attack U.S. interests are already doing so.

"Although there may be some demonstrations and even some violence, I don’t think that it will particularly directly endanger Americans or American allies because those who represent a danger are already doing everything they can to inflict harm," said retired Air Force Maj. Gen. Charles Dunlop, a law professor at Duke University. "After all, ISIS (the Islamic State) is beheading innocent Americans and others. They hardly need more motivation for barbarism."

Many of the report’s conclusions were previously known, and it appeared unlikely that the findings would trigger a new criminal investigation following a Justice Department decision in September 2012 to close for lack of "admissible evidence" a three-year probe without bringing any charges despite the deaths of two detainees.

But the release of the executive summary was certain to ignite a fresh political firestorm, with some lawmakers, human rights groups and others demanding the reopening of a criminal inquiry and CIA reforms.

"A conclusion that most people who will read the report will make is that the CIA was an agency — and still is an agency — that is out of control and not subject to the constitutional system of checks and balances," said Christopher Anders, senior legislative counsel for the American Civil Liberties Union. "The agency itself is in need of serious major reform, and reform has to come from the president and Congress working together."

The investigation has been marred by an unprecedented breakdown in relations between the committee and the CIA over the agency’s monitoring of computers used by the Democratic staff to review the more than 6 million pages of emails, cables and other top-secret documents on which the report is based.

The CIA accused the Democratic staffers of removing without authorization highly classified documents from a top-secret agency reading room in Northern Virginia. The Justice Department declined to open criminal investigations into either matter, and — according to the Huffington Post — the Senate Sergeant at Arms Office, the chamber’s law enforcement agency, dropped an investigation looking into the alleged classified document removal allegation.

Other major conclusions of the investigation:

— The spy agency failed to keep an accurate count of the number of detainees it confined and those subjected to the so-called "enhanced interrogation techniques."

— The CIA impeded effective oversight over the program by the Bush administration, Congress and the agency’s own inspector general’s office.

— The CIA manipulated media coverage of the issue by coordinating the release of inaccurate classified information.

— The use of torture damaged the United States’ "global reputation."

Jonathan S. Landay, Marisa Taylor and David Lightman, McClatchy Washington Bureau (TNS)

(Hannah Allam, Anita Kumar and Nancy A. Youssef of the Washington bureau contributed.)