WASHINGTON — Secretary of State Hillary Rodham Clinton insisted this morning that the department is moving swiftly and aggressively to strengthen security at U.S. installations missions worldwide after the deadly Sept. 11 raid on the consulate in Libya.

In probably her last appearance on Capitol Hill as America’s top diplomat, Clinton once again took full responsibility for the department’s missteps leading up to assault at the U.S. Consulate in Benghazi, Libya that killed Ambassador Chris Stevens and three other Americans.

Clinton said the work was 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 said.

Clinton said the department is implementing the 29 recommendations of an independent review board that harshly criticized the department as well as going above and beyond the proposals, with a special focus on high-threat posts.

“Nobody is more committed to getting this right,” she told the Senate Foreign Relations Committee. “I am determined to leave the State Department and our country safer, stronger, and more secure.”

Her testimony focused not only on the attack but the growing threat from extremists in northern Africa, pointing out that Libya was not an isolated incident.