Secretary of State Hillary Clinton on Wednesday took on Republican congressional critics of her department's handling of the deadly September terrorist attack in Libya.

Conservative GOP members challenged Clinton on the lack of security at the diplomatic compound in Benghazi as well as the erroneous account that the attack grew spontaneously from a protest over an anti-Islam film produced in the United States.

At two hearings, which together totaled more than five hours, Clinton acknowledged a "systemic breakdown" cited by an independent review of issues leading up to the armed assault and said her department was taking additional steps to increase security at U.S. diplomatic facilities.

Here are five things we learned from the hearings before the Senate Foreign Relations and House Foreign Affairs committees.

1. What Clinton did the day of the Benghazi attack

Clinton spent the better part of last September 11 trying to get a handle on security at several other U.S. embassies in the Middle East where anti-American protests were in full swing over an anti-Muslim film produced in the United States.

She said the U.S. embassy was "under assault" by crowds trying to scale the wall. American embassies in Yemen and Tunisia were also facing a "serious threat. Clinton personally called the president of Tunisia, she said, to "beg him to send reinforcements, which he did, to finally save our embassy."

By 4 p.m. that day, Clinton was notified about the Benghazi attack. In the coming hours, she was in meetings and spoke with staff, the American Embassy in Tripoli and other U.S. officials.

Directing the U.S. response from the State Department, Clinton stayed in touch with officials across the administration and with the Libyan government.

She instructed her staff to "consider every option, to just break down the doors of the Libyan officials to get as much security support as we possibly could."

Clinton said in the hours and days following the attack in Benghazi, there were "no delays in decision-making. No denials of support from Washington or from our military," something an independent board established to review the matter cited in its report.

2. U.S. diplomatic posts in some 20 countries under threat

Clinton said threats to U.S. diplomatic posts are ongoing.

"Sitting here today, we probably have at least 20 other posts that are under a serious threat environment as I speak to you," she told senators. "We operate in places where we know that our facilities are being surveilled for potential attacks where we have a steady Intel stream of plotting."

Clinton detailed what the State Department has done to begin implementing the 29 recommendations of the Accountability Review Board to improve security at diplomatic posts in high-threat areas, in addition to a few of her own.

Specifically, Clinton has appointed a team, led by her deputy, to focus on tightening security, sent joint teams of military special forces and diplomatic security threat analysts to more than a dozen high-risk posts and appointed a senior official to focus exclusively on those areas.

The State Department is also working to streamline requests for security so they make their way more quickly up the chain of leadership.

Despite the threat, Clinton stressed the importance of U.S. leadership and diplomatic presence in the Middle East.

"We've come a long way in the past four years, and we cannot afford to retreat now," Clinton told senators. "When America is absent, especially from unstable environments, there are consequences. Extremism takes root, our interests suffer, our security at home is threatened."

3. Clinton not shying away from a fight

Clinton grew emotional and held back tears when talking about U.S. personnel killed in the Benghazi attack.

"For me, this is not just a matter of policy, it's personal. I stood next to President Obama as the Marines carried those flag-draped caskets off the plane at Andrews," Clinton said as she choked back tears. "I put my arms around the mothers and fathers, the sisters and brothers, the sons and daughters, and the wives left alone to raise their children."

But she lost patience with the focus of Republican senators on talking points used by U.N. Ambassador Susan Rice on the next Sunday's talk shows that focused on a protest at the U.S. post in Benghazi, which turned out not to have taken place.

When Sen. Ron Johnson pressed Clinton on why the State Department didn't call U.S. personnel who were evacuated from Benghazi to determine whether there was a protest, Clinton took him to task.

"With all due respect, the fact is we had four dead Americans," Clinton reminded Johnson as she banged her hand on the table.