Secretary of State Hillary Rodham Clinton urged lawmakers Wednesday to focus on how the United States can improve security and diplomacy in unstable regions such as North Africa in the future, rather than dwell on past statements about the attack on an American compound in Benghazi, Libya, in September and the motivation of the attackers.

“It is, from my perspective, less important today looking backwards as to why these militants decided” to attack the Benghazi facility, Clinton testified at the Senate Foreign Relations Committee on Wednesday morning. Rather, the United States needs to be “looking forward,” she said.

“Libya is still dangerous. It is still in a very unstable status. And whatever we can do for them, we at least ought to agree we need to do and get out there and start delivering,” she said.

It was an emotional day on Capitol Hill for Clinton, who also testified before the House Foreign Affairs Committee in the afternoon. In one of her final appearances as secretary of State, she choked up as she recalled greeting the flag-draped coffins of the four Americans killed in Benghazi, which she said she felt responsible for.

She also displayed flashes of anger when responding to Republican accusations that the Obama administration played politics in its characterizations of the attack, which took place during the homestretch of the presidential election.

As they have for months, GOP lawmakers zeroed in on United Nations Ambassador Susan E. Rice’s comments on Sunday news programs, five days after the attack, that it had evolved out of protests against an anti-Muslim video.

“We were misled that there were supposedly protests and then … an assault sprang out of that,” said Sen. Ron Johnson, R-Wis., a new member of the Foreign Relations panel. “And that was easily ascertained that that was not the fact and the American people could have known that within days.”

Clinton denied that, noting that it took weeks for Washington officials to piece together the full picture and timeline of the attack. The independent review board appointed by the State Department found that there are still questions about the attackers’ motivations and planning, she pointed out.

Johnson kept pressing, and Clinton finally exploded. “With all due respect, the fact is, we had four dead Americans,” she said, voice raised. “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? It is our job to figure out what happened and do everything we can to prevent it from ever happening again.”

To that end, the review board issued 29 recommendations in a report last month to help shore up security in high-threat posts, as well as address some of the bureaucratic roadblocks that hindered communications around Benghazi.

In hindsight, it has become clear that security at that compound was woefully inadequate, Clinton conceded. She testified that specific security requests for the U.S. consulate in Benghazi coming in the summer before the attack never rose to her level.

“I didn’t see those requests, they didn’t come to me, I didn’t approve them, I didn’t deny them,” Clinton told lawmakers.

Sen. Rand Paul, R-Ky., responded that “it was a failure of leadership not to know these things.”

“Had I been president at the time and I found that you did not read the cables from Benghazi … I would have relieved you of your post,” he said.

The Accountability Review Board “made very clear that the level of responsibility for the failures that they outlined was set at the assistant secretary level and below,” Clinton responded.

The State Department is now implementing all the recommendations released by that board in December.

Clinton told lawmakers that “fully 85 percent” of the tasks that the department developed out of those recommendations “are on track to be completed by the end of March, with a number completed already.”

The State Department is also instituting an annual High Threat Post Review chaired by the secretary of State.

Clinton, who is expected to be replaced by Sen. John Kerry, D-Mass., in the coming weeks, urged lawmakers to work with the State Department going forward to “really understand and address the resources, support and changes that are needed to face what are increasingly complex threats.’”

Democrats, notably Robert Menendez of New Jersey, Foreign Relation’s presumed next chairman, and House Foreign Affairs ranking member Eliot L. Engel of New York, called on their fellow lawmakers to support more funding for diplomatic security, which they noted has not met State Department requests in recent years.

Menendez also supported Clinton’s calls to alter contracting laws, which, according to Clinton, require the State Department to accept the lowest-priced contract for security guards.

“We have requested a change in the legislation that would allow us to use some discretion to try to deal with the varieties and vagaries of these local guard forces,” Clinton told the House Foreign Affairs Committee.

Separately, Sen. Patrick J. Leahy, the top appropriator for the State Department, blasted House Republicans for not including a Senate-backed provision to bolster embassy security from an emergency supplemental spending measure (HR 152) the House passed last week.

“For Republicans to blame the administration for failing to protect our diplomats, without acknowledging their own efforts to slash resources for embassy security, is pure, distilled hypocrisy,” Leahy said Wednesday in a written statement.

A number of Republicans commented that it’s not clear money itself is the issue.

“This committee would have no idea whether the appropriate amount of money is being spent, or if that could have prevented what happened in Benghazi because we’ve never done an authorization … never done the kind of oversight that this committee ought to do,” Senate Foreign Relations ranking Republican Bob Corker of Tennessee said in his opening remarks.

Clinton heartily supported Corker’s call for the committee to restart the practice of passing authorization bills for the State Department, which she said could better bring in line foreign policy between the administration and Capitol Hill.

“I know that you share our sense of responsibility and urgency,” Clinton told the Senate panel. “And while we all may not agree on everything, let’s stay focused on what really matters: protecting our people and the country we all love.”