Secretary of State Hillary Clinton has insisted that her department is moving swiftly and aggressively to strengthen security at US missions worldwide after the deadly September 11 raid on the consulate in Libya.
In her last formal congressional testimony as America's top diplomat, Mrs Clinton, at times emotional and fierce, once again took full responsibility for the department's mistakes leading up to assault at the US facility in Benghazi, Libya, that killed Ambassador Chris Stevens and three other Americans.
Mrs Clinton's testimony was focusing on the Libya attack after more than three months of Republican charges that the Obama administration ignored signs of a deteriorating security situation there and cast an act of terrorism as mere protests over an anti-Muslim video in the heat of a presidential election.
Washington officials suspect that militants linked to al Qaida carried out the attack. As she began her testimony, her voice cracking at one point, Mrs Clinton said her experience was sometimes highly personal.
"I stood next to President Obama as the Marines carried those flag-draped caskets off the plane at Andrews. I put my arms around the mothers and fathers, sisters and brothers, sons and daughters," she told the Senate Foreign Relations Committee.
Her voice rising at another point, she defended UN Ambassador Susan Rice, who was vilified for widely debunked claims five days after the attack that protests precipitated the raid rather than terrorism. She challenged the Republican focus on Ms Rice's comments, which were based on intelligence talking points.
"The fact is we had four dead Americans. Was it because of a protest? Or was it because of guys out for a walk one night who decided they'd go kill some Americans? What difference, at this point, does it make?" a clearly exasperated and angry Mrs Clinton told Republican Senator Ron Johnson. "It is our job to figure out what happened and do everything we can to prevent it from ever happening again, senator."
She insisted that "people were trying in real time to get to the best information", and that her focus was on looking ahead on how to improve security rather than revisiting the talking points and Ms Rice's television appearance. As Republican criticism of her mounted, Ms Rice was forced to withdraw her name as a possible successor to Mrs Clinton.
Mrs Clinton said the department is implementing the 29 recommendations of an independent review board that harshly criticised the department as well as going above and beyond the proposals, with a special focus on high-threat posts.
The review board report faulted "systematic failures and leadership and management deficiencies at senior levels within two bureaus of the State Department" and four employees were put on administrative leave. He said: "Nobody is more committed to getting this right. I am determined to leave the State Department and our country safer, stronger, and more secure."