Calls for additional security at a US consulate in Libya were turned down ahead of an attack which killed ambassador Chris Stevens and three other Americans, a congressional hearing in Washington has been told.
Eric Nordstrom, the former chief security officer for US diplomats in Libya, said his request was blocked by a department policy to "normalise operations and reduce security resources".
Another witness, Lieutenant Colonel Andrew Wood, who left Libya in August, said: "The security in Benghazi was a struggle and remained a struggle throughout my time there."
The former head of a US special forces team that helped protect the embassy in Tripoli, told the House Oversight and Government Reform Committee security was so weak that in April only one diplomatic security agent was stationed in Benghazi.
State Department officials told the committee the number of US and local security guards at the consulate was adequate for the threat level at the time, but the compound was overrun by an "unprecedented attack".
"We had the correct number of assets in Benghazi at the time of 9/11," said Charlene Lamb, deputy secretary of state for diplomatic security, in charge of protecting American embassies and consulates around the world.
There were five diplomatic security agents at the consulate at the time of the attack in September, along with additional Libyan guards and a rapid response team at a nearby annex, she said.
She also rejected assertions that an extension of Lt Col Wood's mission could have made a difference during the attack.
"It would not have made any difference in Benghazi," she said, pointing to the fact that his team was based in Tripoli and spent nearly all of its time there.
The State Department's initial response to the attack on September 11 and subsequent allegations of serious security failings by government officials is being scrutinised by the main watchdog in the Republican-controlled House of Representatives.
The case has become a major issue in the presidential campaign, with Republican candidate Mitt Romney calling it an example of President Barack Obama's weakness in foreign policy matters.
Ahead of the hearing, two State Department officials on Tuesday described the attack as a relentless assault in which dozens of armed men invaded the consulate compound, setting it on fire and hunting through the building for staff.
The new account contradicts initial reports by State Department officials which said it was a "spontaneous" attack sparked by a protest against an anti-Islam film circulating on the internet.
"There was no actionable intelligence of any planned or imminent attack," according to one top State Department official, who gave the information anonymously.