The State Department's former point man on security in Libya told a congressional hearing Wednesday that his superiors worked against him as he tried to get more help for the U.S. diplomatic mission in Benghazi in the months before it was overrun in a deadly terror attack.

Eric Nordstrom, the one-time regional security officer, told the House Oversight Committee that he had a disheartening conversation with the regional director of the agency's Bureau of Near Eastern Affairs when he requested additional manpower for the facility.

"I said, 'Jim, you know what makes it most frustrating about this assignment? It's not the hardships. It's not the gunfire. It's not the threats. It's dealing and fighting against the people, programs, and personnel who are supposed to be supporting me," Nordstrom said.

He also told the State Department officer, "'For me, the Taliban is on the inside of the building."

That bombshell ended a contentious hearing during which two State Department officials defended the Obama administration's handling of the September 11 attack that killed Ambassador Christopher Stevens and three other Americans.

Benghazi has become a flashpoint in the presidential campaign with Republican Mitt Romney saying the attack illustrates that President Barack Obama's policies have made America less influential and more vulnerable around the world.

Under Secretary of State for Management Patrick Kennedy responded to suggestions the State Department was responsible for a lack of preparedness.

"We regularly assess risk and resource allocation, a process involving the considered judgments of experienced professionals on the ground and in Washington, using the best available information," Kennedy said.

The assault on the U.S. compound was "an unprecedented attack by dozens of heavily armed men," Kennedy said.

His colleague, Deputy Assistant Secretary of State for International Programs Charlene Lamb, added that the State Department "had the correct number of assets in Benghazi at the time," drawing a sharp rebuke from committee Chairman Rep. Darrell Issa, R-California.