The United States had an unmanned Predator drone over its consulate in Benghazi during the attack that slaughtered four Americans — which should have led to a quicker military response, it was revealed yesterday.

“They stood, and they watched, and our people died,” former CIA commander Gary Berntsen told CBS News.

The network reported that the drone and other reconnaissance aircraft observed the final hours of the hours-long siege on Sept. 11 — obtaining information that should have spurred swift action.

But as Ambassador Christopher Stevens and three colleagues were killed by terrorists armed with AK-47s and rocket-propelled grenade launchers, Defense Department officials were too slow to send in the troops, Berntsen said.

“They made zero adjustments in this. You find a way to make this happen,” he fumed.

“There isn’t a plan for every single engagement. Sometimes you have to be able to make adjustments.”

The Pentagon said it moved a team of special operators from Central Europe to Sigonella, Italy — about an hour flight from Libya — but gave no other details.

Fighter jets and Specter AC-130 gunships — which could have been used to help disperse the bloodthirsty mob — were also stationed at three nearby bases, sources told the network.

When the attack began, Chairman of the Joint Chiefs Martin Dempsey and Defense Secretary Leon Panetta “looked at available options, and the ones we exercised had our military forces arrive in less than 24 hours, well ahead of timelines laid out in established policies,” a White House official told the network.

Even as the administration continues to vow that the perpetrators will be brought to justice, the man identified by witnesses as a ringleader in the attack continues to walk the streets of Libya without fear of arrest.

Ahmad Abu Khattala has admitted being at the consulate during the horrific attack but has yet to be questioned by any Libyan authorities.

Abu Khattala spoke to a New York Times reporter Thursday from a hotel patio as he sipped a strawberry frappe and mocked the US and Libyan governments.

“These reports say that no one knows where I am and that I am hiding,” he boasted. “But here I am in the open, sitting in a hotel with you. I’m even going to pick up my sister’s kids from school soon.”

Lax security at the consulate was an open secret.

Stevens wrote a cable in June that there wasn’t enough security at the consulate, and he noted there had been a recent spike in attacks against “international organizations and foreign interests,” ABC News said.

The ambassador wrote another cable in August that read, “A series of violent incidents has dominated the political landscape during the Ramadan holiday.”

Stevens said that the incidents were “organized” and that the Libyan security force had “not coalesced into a stabilizing force and [provided] little deterrence.”

Several requests for additional security in Benghazi were made to the State Department prior to the attack. They were all rejected.

Secretary of State Hillary Rodham Clinton tried to deflect blame from President Obama last week, saying the decision not to beef up guards was her responsibility.

“I’m in charge of the State Department’s 60,000-plus people all over the world [at] 275 posts,” she told CNN.

“The president and the vice president wouldn’t be knowledgeable about specific decisions that are made by security professionals. They’re the ones who weigh all of the threats and the risks and the needs and make a considered decision.”

The attack has become a major issue in the presidential campaign, with Mitt Romney saying Obama’s failure to safeguard the consulate highlights his failure in foreign policy.

Romney has also hammered Obama for failing to immediately label it a terror attack and the administration for changing its story about whether the attack was a protest over an anti-Islamic movie or a coordinated strike.

The tragedy — and alleged security lapses leading up to the attack — will likely be brought up at tomorrow’s final presidential debate.

The 90-minute debate will be moderated by Bob Schieffer of CBS News. Schieffer has listed five subject areas, with more time devoted to the Middle East and terrorism than any other topic.