EXCLUSIVE: The attack on the U.S. Consulate in Benghazi may have been part of a broader campaign to drive the U.S. and western presence -- and particularly a growing CIA contingent -- out of eastern Libya, two military sources told Fox News.

The Sept. 11 attack was preceded by hundreds of security incidents in Libya over the past year. Several of them involved western targets in the Benghazi area, which could indicate a pattern.

The attack on the U.S. Consulate in June 6 with an improvised explosive device, planted in the ledge of the perimeter wall, was described as a probing attack to measure the response. This incident, coupled with attacks on the International Red Cross and an RPG attack on the British ambassador's convoy -- after which the British withdrew -- suggest a pattern to drive western influence from the region.

Further, it fits with a broader effort by the Al Qaeda affiliate and the militant group Ansar al-Sharia to establish an Islamic state in eastern Libya. Libyan authorities are identifying Ansar al-Sharia leader Ahmed Abu Khattala as the commander of the attack, though Fox News was told the U.S. intelligence community is not going quite that far. Rather, Khattala is on the short list of suspects and was described as "one to watch."

The Libyans are citing eyewitness accounts that Khattala was at the scene in Benghazi, leading the assault. Khattala is considered a hardcore Islamist who was imprisoned under Muammar Qaddafi.

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Those militants are also capitalizing on the proliferation of weapons, including portable surface-to-air missiles called MANPADS, since the fall of the Qaddafi regime.

Former CIA Director Porter Goss said the idea that militants were trying to achieve the expulsion of western forces and diplomats from the region "is a very accurate assessment."

He said they likely "are trying to create more sanctuary areas by pushing us out -- our diplomats, our military."

A representative with the CIA declined to comment for this report.

The speculation about the motive for and cause of the attack comes as officials in Washington try to get to the bottom of why administration officials initially described the strike as a spontaneous reaction to an anti-Islam film.

The head of the Senate Intelligence Committee, Sen. Dianne Feinstein, said an intelligence error is to blame.

"I think we do know what happened now. There's no question but that it was a terrorist attack, there is no question but that the security was inadequate and I think that there is no question that we need to work on our intelligence," she said in a recent interview with a local CBS station in San Francisco.

She said it was probably a mistake by Director of National Intelligence James Clapper to put out talking points on the initial intelligence assessment which implied a link to the video.

The administration, though, has not ruled out that the video may have played a role -- though it now describes the assault as a coordinated terror attack.

Fox News was told that chatter was picked up in the first 72 hours after the attack that pointed to the assault being quickly thrown together, even on that day, with militants taking their cue from the strong visuals of the U.S. Embassy in Cairo being overrun.

Neither Al Qaeda in the Islamic Maghreb nor Ansar al-Sharia has publicly taken credit for the attack. Sources, though, did not say whether they might be staying quiet simply because of an expectation that the U.S. will retaliate against them.

Still, Fox News was told "there is no doubt militants from Ansar al-Sharia were involved," adding some have ties to the Al Qaeda affiliate in North Africa -- though they said it does not appear that affiliate planned the attack.