Updated

Security measures at U.S. diplomatic posts are being called into question in the wake of the deadly attack on the consulate in Benghazi.

Despite the fact that it was the 11th anniversary of Sept. 11 and the leader of Al Qaeda had recently released a video calling on militants to attack Americans, there were no Marines guarding the compound Tuesday in eastern Libya -- a still-restive region.

Instead, U.S. diplomats were relying on a mix of Libyan and American security personnel to protect them. This included a local guard contingent outside the compound. It wasn't enough to prevent four Americans from being killed, in addition to others who were wounded.

Retired Gen. Jack Keane, former vice chief of staff for the U.S. Army, said Thursday that the compound was "inadequately protected."

"That's an issue we've got to resolve," he told Fox News. "We've got to reassess the security."

The Obama administration has ordered its diplomatic posts to assess their security situation and make any necessary changes. It's unclear what, if any, those might be -- as demonstrations continue in Cairo and also spread to the U.S. Embassy in the capital city of Yemen and beyond.

The situation at the Benghazi consulate was unique in that it was an interim facility, one acquired by the U.S. before the fall of Muammar Qaddafi. It included one main building, several "ancillary buildings" and an annex, according to officials.

Still, the security there might not be that different from security at other U.S. consulates. One administration official told FoxNews.com "we have a number of posts where we handle security in the same manner as it was handled" in Benghazi.

The official said the security is handled "mission by mission," while indicating the Marine presence is more common at embassies as opposed to consulates.

"There are Marines at some consulates, not at all," the official said. "There are Marines at most embassies, but not at all."

Officials defended the set-up at Benghazi. One said they had a "robust American security presence inside the compound, including a strong component of regional security officers." They also had the local guard force outside, "which is similar to the way we are postured all over the world," and a "physical perimeter barrier."

Former CIA officer Mike Baker said that, looking back, it appears security should still be improved.

"We know that there's chaos in Libya. We know there's been chaos ever since the revolution," he told Fox News. "Yes, in hindsight obviously ... there should have been significantly more security on the ground protecting this."

He said Marine security guards are "fantastic," but "they need to be present in order to make a difference."

James Carafano, a foreign policy and defense analyst with the Heritage Foundation, said it doesn't matter so much whether the security force is composed of Marines or private contractors. The basic question, he said, is whether they are appropriately equipped and prepared.

A 50-member Marine unit was dispatched Wednesday to Tripoli to help secure the U.S. Embassy there. Staff have been evacuated from the Benghazi compound. Questions continue to swirl about whether the Benghazi assault was in fact a coordinated strike, timed for the Sept. 11 anniversary, and not a spontaneous protest over an anti-Islam film.

But lawmakers are looking to dig deep to find out what went wrong. Sen. James Inhofe, R-Okla., said in a statement Wednesday that he's calling for Senate hearings on the tragedy, with security among the issues he wants examined.

"There are many disturbing facts about these attacks that raise many troubling questions.  For this reason, today I am calling on (two Senate committees) to hold hearings immediately on the lack of intelligence, security, and appropriate response," he said. "We must have answers to these questions to prevent similar attacks in the future."

Sen. Marco Rubio, R-Fla., after an intelligence briefing, also said Thursday that host countries need to do more to protect U.S. diplomatic compounds.