Updated 7:25 p.m. ET

The State Department renewed the lease for the U.S. compound in Benghazi two months before the Sept. 11, 2012 terrorist attacks without requiring the facility to meet normal security standards. That news comes from an interview Sen. Lindsey Graham, R-S.C., conducted with a survivor of the attacks.

The survivor, a State Department diplomatic security agent whose name isn't being disclosed, spoke behind closed doors in late November to Senators Graham, Bob Corker, R-Tenn., and Robert Menendez, D-N.J. The previously-undisclosed existence of the year-long lease calls into question the State Department's designation of the compound as "temporary" and therefore exempt from normal security requirements.

According to the Accountability Review Board (ARB) that investigated security shortfalls, a "key driver behind the weak security platform in Benghazi was the decision to treat Benghazi as a temporary, residential facility...This resulted in the Special Mission compound being excepted from office facility standards and accountability" under federal law. The ARB said Benghazi's security was "far short" of standards from the start in November 2011 and "remained so even in September 2012, despite multiple field-expedient upgrades funded by [diplomatic security]."

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A State Department official told CBS News that although the facility was exempt from normal requirements, a long list of improvements was made to physical security including concrete jersey barriers, barbed wire and hardened safe rooms with steel doors. As to what makes a facility considered "temporary" even with a year-long commitment, the State Department told CBS News "a temporary facility is one we occupy in a place where we have not yet decided to have a permanent diplomatic presence."



The lease renewal came shortly after a June 2012 assault in which an improvised explosive device blew a giant hole in the exterior wall of the facility. Graham also says he learned that in addition to other denied requests, the State Department's Regional Security Officer for Libya asked for stronger security for the compound in August 2012 but it was denied. The State Department told CBS News that the August 2012 request for more security was not submitted to headquarters, so there was no denial.

"Don't you imagine that if Congress had known that someone renewed a formal lease for one year at the same time it called the facility 'temporary' and exempted it from security standards that we would have had a lot of questions about it?" Graham said in an interview with CBS News.

Four Americans including U.S. ambassador Christopher Stevens were murdered in the terrorist attacks.

According to a document produced by the State Department, the U.S. was paying $168,000 annually for part of the U.S. Benghazi compound known as Villa B, and $336,000 for Villa C. Both leases were renewed for one year in July of 2012.

The State Department witness also said he never reported a protest. and watched 15-20 armed insurgents on video camera as they stormed the compound, according to Graham. The witness said the attackers carried a banner that was later identified to represent the radical Islamist group Ansar al-Sharia.

In late October, Graham temporarily blocked President Obama's nominees from being confirmed in the Senate until the State Department agreed to make survivors of the Benghazi attacks available for questioning. He's still pressing to speak with others. The State Department previously said that allowing witnesses to testify or release their statements could jeopardize a criminal investigation and had no immediate comment for this report.

The FBI will not release transcripts of interviews it conducted with all of the survivors immediately after the attacks, but Graham says the FBI told him over the Christmas break that none of the survivors mentioned protests.