"There's no question that the security was not enough to prevent that tragedy from happening," spokesman Jay Carney told reporters as Republicans suggested at a congressional hearing that Obama administration lapses contributed to the deaths.
"There is no question that when four American personnel are killed in an attack on a diplomatic facility, that the security there was not adequate to prevent that from happening," Carney repeated. "It is not an acceptable outcome, obviously, that four Americans were killed."
U.S. Ambassador to Libya Christopher Stevens, Foreign Service Information Management Officer Sean Smith and private security employees and former U.S. Navy SEALs Glen Doherty and Tyrone Woods were killed in a 5-hour attack Sept. 11 on the unmarked mission and nearby annex with rocket-propelled grenades, hand grenades, AK-47 and FN F2000 NATO assault rifles, gun trucks and mortars.
Security officials in Libya "repeatedly warned Washington officials of the dangerous situation" there, House Committee on Oversight and Government Chairman Darrell Issa, R-Calif., said in his opening statement. "Washington officials seemed preoccupied with the concept of normalization."
Committee Democrats said Republicans had voted to cut some of the very funding for security they suggested was lacking in Libya.
Rep. Elijah E. Cummings of Maryland, the committee's top Democrat, called on House GOP leaders to support a supplemental funding bill to restore diplomatic security resources.
The committee released a copy of a diplomatic cable written by Stevens the day he died in which he expressed concerns about rising violence and militant Islamist influence in eastern Libya but did not ask for more protection.
A State Department official acknowledged to the committee the department's Bureau of Diplomatic Security rebuffed appeals for more security in Libya before the attack.
Deputy Assistant Secretary of State Charlene Lamb told the committee she opposed a request to extend the term of a special supplemental military security team that had assisted Stevens and other diplomats from February until August.
Extending the term, Lamb said, "would not have made any difference in Benghazi" because the team was based in the capital Tripoli, 630 miles away.
State Department Undersecretary for Management Patrick F. Kennedy said none of the security requests by Eric A. Nordstrom -- the department's former regional security officer who Lamb rebuffed -- or Army Special Forces security team commander Lt. Col. Andrew Wood, stationed at the U.S. Embassy in Tripoli, would have altered the Benghazi outcome.
The attack was "an unprecedented assault by dozens of heavily armed men," Kennedy said.
Nordstrom acknowledged to the committee, "Having an extra foot of wall, or an extra-half dozen guards or agents would not have enabled us to respond to that kind of assault."