WASHINGTON -- The pivotal role of the Central Intelligence Agency in the deadly attack in Benghazi, Libya, last month burst into the public spotlight late on Thursday, after a series of news reports added another layer of complication to a controversy that has loomed over the final days of the presidential election.

Several of the articles -- the product of a background briefing by American intelligence officials, the first official acknowledgement of the extent of the CIA's role -- laid out a detailed timeline of the CIA's actions on the ground during the attack.

The attack on Sept. 11 against the U.S. diplomatic compound in Benghazi by an armed Islamic militant group ultimately left four Americans dead, including the U.S. ambassador to Libya, Christopher Stevens. CIA operatives were at the compound within 25 minutes of the assault, and played a major role in helping fight off the attack over the next several hours, the intelligence officials told reporters. Two operatives would later die in the fighting that night.

The fact that the CIA had a facility at the compound in Benghazi had been an open secret for weeks, although its central role was not fully acknowledged.

A Fox News report last Friday had alleged that several operators at an agency annex had been denied help from their CIA higher-ups during the fighting, something the CIA denies, and there had even been indelicate hints of secret components to the Benghazi compound during an open hearing on Capitol Hill back in mid-October.

A U.S. official familiar with the Benghazi intelligence, who spoke under the condition of anonymity to discuss sensitive matters, confirmed to HuffPost that the CIA had an extensive presence in Benghazi, and that the two former Navy SEALs who died in the assault, Glen Doherty and Tyrone Woods, were contractors working for the agency.

According to documents released by the House Oversight Committee, when the Undersecretary of State for Management Patrick Kennedy signed an order last December to maintain a presence in the Benghazi compound for another year, his official memo counted 35 "U.S. government personnel," of whom only eight were State Department. Many of the rest were secretly with the CIA, the official confirmed.

The U.S. official noted that at no point in the October congressional hearing did any of the State Department officials testifying use the word "consulate" to describe the Benghazi compound. This was no accident. In fact, the compound served little routine diplomatic purpose, and was largely under the operational control of the CIA.

Republicans and conservative media outlets, particularly Fox News, have repeatedly faulted the Obama administration, and in particular the State Department, for its immediate handling of the crisis, and for its incomplete and sometimes inaccurate description of events after the attacks in Benghazi.

Some, like Rep. Jason Chaffetz (R-Utah), have alternated between publicly urging the release of more information and cautioning against the risk of revealing government secrets. During the October congressional hearing, Chaffetz had halted the testimony of a State Department official when she brought up the annex, out of concerns that her remarks might "deal with sources and methods that would be totally inappropriate in an open forum such as this."

"Sources and methods" is widely understood to be a term that refers to intelligence operations.

The involvement of the CIA may help explain, if not quite justify, some of the evident disarray around the administration's handling of the attacks, former agency officials told HuffPost. When secret agencies are involved, and especially when they are as pivotal as they were in Benghazi, public explanations can be treacherous, and officials will go out of their way to avoid exposing the agency's role, especially if the operations could be ongoing.

"The CIA can't admit their role because it compromises the cover of the facility, and that's the most important thing," said Bob Baer, who spent two decades as a field officer in the CIA. "You can never compromise cover."

It's not a perfect explanation. The Obama White House has shown a willingness to part with sensitive information in the past when it suits them, most notably in the aftermath of the Osama bin Laden raid. Before that raid, the very existence of a top unit of Navy SEALS known as Team Six, or the Devgru, had been considered an unmentionable secret.

And the prominent involvement of the CIA in Benghazi raises as many questions as it resolves, including why there was so little intelligence ahead of the attack, and insufficient manpower to protect against it.

But there were other potentially mitigating consequences of the CIA's significant involvement in the facility, the U.S. official told HuffPost. For one thing, according to an in-depth investigation by The Wall Street Journal on Thursday, it was partly confusion over who had ultimate responsibility for security at the compound, particularly in an emergency situation like the September attack, that contributed to the disarray during the response.

"State Department officials believed that responsibility was set to be shouldered in part by CIA personnel in the city through a series of secret agreements that even some officials in Washington didn't know about," the Journal wrote.

The Journal's report placed the blame for many of the missteps in Benghazi specifically on CIA director David Petraeus, who was described as aloof in the weeks after that episode. Petraeus was faulted for failing to attend the funeral of the two former Navy SEALS, both identified as CIA contractors, who died during the attack, and for later attending a screening of the spy-thriller "Argo" amid sensitive internal deliberations.

A senior intelligence official disputed this characterization to the Journal, calling Petraeus "fully engaged from the start."

The U.S. official told HuffPost that a two-day delay in publicly identifying Woods and Doherty was a consequence of the unique sensitivity of determining whether they would be outed as CIA agents, or if the State Department would claim the two as theirs.

Both Woods and Doherty were ultimately identified vaguely as Embassy "security officers."

And, according to the Journal, part of the reason for an extensive hold-up in securing the main diplomatic compound -- where many papers belonging to Ambassador Stevens were later recovered by reporters -- was because resources had been redirected to secure the CIA annexes.

Paul Pillar, a Georgetown University professor and 28-year CIA veteran, told HuffPost that a bigger problem for making sense of the early hours and days of the attack was "the understandably fragmentary and inconclusive nature of early reporting when anything like this happens."

"That would have been the case regardless of which specific agencies were involved on the ground in Benghazi," he added. But the "direct involvement of an intelligence agency on the ground can be an added matter of delicacy in making public statements about a situation."

Also on HuffPost:

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  • U.S. President Barack Obama

    "The United States condemns in the strongest terms this outrageous and shocking attack. ... Make no mistake: We will work with the Libyan government to bring to justice the killers who attacked our people. ... We reject all efforts to denigrate the religious beliefs of others, but there is absolutely no justification for this type of senseless violence, none." (AP Photo/Evan Vucci)

  • British Prime Minister David Cameron

    "This senseless attack ended the lives of people who had worked selflessly alongside Libyans during their darkest days. ... We look to the new Libyan authorities to do all in their power, as they have pledged to do, to bring the killers to justice. Britain stands ready to assist Libya and the United States in that task. Above all, we will honor the memory of these dedicated people by continuing their work to help Libyans build a secure and free country." (AP Photo/Ben Stansall, Pool)

  • Hamid Karzai

    "The Islamic Republic of Afghanistan strongly condemns this inhuman and insulting action (the film) and shows its strong hatred against this action. Insulting the messenger of Islam is to insult the values of 1.5 billion Muslims around the world. This insulting action will cause enmity and contrast between religions and cultures in the world and will be a strong punch to peace and harmony between humans."(AP Photo/Ahmad Massoud / Xinhua, Pool)

  • Pakistan's Foreign Ministry

    "Such abominable actions, synchronized with commemoration of atrocious events like 9/11, provoke hatred, discord and enmity within societies and between peoples of various faiths. The event has deeply hurt the feelings of the people of Pakistan and the Muslims all over the world." (AP Photo/Brendan Smialowski, Pool)

  • Hezbollah

    The movie is an "immoral act that represents the highest levels of aggression against human rights that is represented by the respect of people's beliefs. ... The United Nations should issue laws that criminalize such acts similar to laws that criminalize anti-Semites." (AP Photo/Bilal Hussein)

  • NATO Secretary-General Anders Fogh Rasmussen

    "It is important that the new Libya continues to move toward a peaceful, secure and democratic future."(AP Photo/Shakh Aivazov, Pool)

  • Libyan interim President Mohammed el-Megarif

    "We extend our apology to America, the American people and the whole world." (AP Photo)