A former State Department security official told lawmakers Wednesday that given the unprecedented size and sophistication of the Sept. 11 attack on the U.S. Consulate in Benghazi, Libya, additional security personnel or infrastructure likely would not have overpowered the assault.

Eric Nordstrom, the State Department’s regional security official in the capital of Tripoli through July, testified before the House Oversight and Government Reform Committee that “the ferocity and intensity of the attack,” which killed four Americans, including Ambassador J. Christopher Stevens, “was nothing that we had seen in Libya, or that I had seen in my time in the Diplomatic Security Service.”

“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,” Nordstrom said in his prepared remarks.

Nordstrom said the State Department had three temporary diplomatic security agents posted in Benghazi when he left Libya at the end of July, the minimum security force believed to be necessary.

The statements appear to contradict charges recently leveled by some Republicans probing the attack. Republicans have accused the Obama administration of failing to adequately secure the compound.

Chairman Darrell Issa (R-Calif.) and National Security, Homeland Defense and Foreign Operations Subcommittee Chairman Jason Chaffetz (R-Utah) released information last week based on interviews with whistleblowers who asserted the Obama administration had rejected requests for additional security at the consulate because of political considerations.

“Washington officials seemed preoccupied with the concept of ‘normalization,’” to signal a normal diplomatic presence, rather than acknowledging the serious security threats, Issa said in opening remarks at the first congressional hearing of the attacks.

The statements of committee Republicans are part of a broader and politically charged inquiry of the administration’s security procedures and intelligence assessments in Libya before and after the attack.

Democrats have countered that Republicans are trying to politicize the attack with an eye toward gaining an advantage in the November elections.

Partisan tensions spilled into the open Wednesday, with the committee’s ranking Democrat, Maryland Rep. Elijah Cummings, claiming in his opening statement that the panel’s investigation repeatedly has excluded Democrats. “The chairman has withheld documents that were provided to the committee, which is a violation of House rules,” Cummings said. “And he effectively excluded Democrats from a congressional delegation to Libya this past weekend.”

Issa and Chaffetz, meanwhile, sparred with State Department witnesses over whether the administration had cleared certain documents and other information to share with Congress and the public as part of the hearing.

In addition to committee leaders from both parties, more than a dozen other lawmakers returned to Washington to attend Wednesday’s hearing, an impressive number given that Congress is in recess as lawmakers prepare for the Nov. 6 elections.