During House and Senate hearings on Capitol Hill Wednesday, Clinton conceded reforms are needed, but pushed back against GOP accusations the Obama administration misled the public about the attacks for political reasons.
House Foreign Affairs Committee Chairman Rep. Ed Royce, R-Calif., told Clinton, "Security was not a high priority" at the U.S. Consulate in Benghazi where Ambassador Chris Stevens and three other Americans were killed.
"Security requests were denied," Royce charged.
Democrats have said congressional Republicans cut funding requested by the State Department for embassy security but Royce said the tragedy of Benghazi "was rooted in poor security," not in a lack of funding.
He questioned why security assets were pulled from the region before the attack. Clinton said those assets were focused on the U.S. Embassy in Tripoli, not the consulate in Benghazi.
Rep. Jeff Duncan, R-S.C., accused Clinton of allowing the Benghazi consulate to "become a death trap" and said that was "malpractice."
Rep. Ileana Ros-Lehtinen, R-Fla., pointed out news stories that department officials responsible for not passing on requests for more security to the highest levels were disciplined, and charged the stories were, "Not true!"
Clinton said all four individuals "have been removed from their jobs ... [and] placed on administrative leave." She said federal regulations forbid removing someone because of "unsatisfactory leadership" and urged Congress to change those regulations.
Democrats were more supportive. Rep. Eliot Engel, D-N.Y., the ranking member, said instead of engaging in "gotcha" politics the committee should be working on solutions.
"Clearly mistakes were made, but let's make one thing perfectly clear, Barack Obama was not responsible for the Benghazi attack, just as George Bush was not responsible for the Sept. 11  attacks and Ronald Reagan was not responsible for the [1983 attack on the Marine barracks in Lebanon]," Engel said.
He also raked Congress on funding.
"In the past two years alone, the administration's request for [security funding] has been cut by half-a-billion dollars," he said.
Earlier Wednesday, during a Senate Foreign Relations Committee hearing, U.S. Sen. John McCain, R-Ariz., blasted the administration and Clinton for what he called a failure to help Libya fight terror. McCain said there were plenty of warnings leading up to the attack on the anniversary of the 2001 attacks on the World Trade Center and the Pentagon, but "with all these warnings, we didn't have a single Defense Department" force to come to the aid of the consulate in the event of an attack.
"I categorically reject your answers [about the events leading up to the Benghazi attack and the U.S. response]. ... The American people deserve answers and they certainly don't deserve false answers," McCain said.
Clinton told McCain they would have to disagree on the facts, but, "Since March 11 congressional holds have been placed for many months on aid to Libya. ... We've got to get our act together between the administration and the Congress."
Sen. Rand Paul, R-Ky., called the Benghazi attack "the greatest tragedy" since the Sept. 11, 2001, attacks and told Clinton he would have fired her if he had been president.
Clinton told the panel every crisis should not be turned into a political football, but everyone should "be smart about this" and seek to prevent such tragedies in the future.
Clinton said U.S. Ambassador to the United Nations Susan Rice did not mislead the public about the Libyan terror attack.
Rice told interviewers shortly after the Sept. 11 attack, the assault in Benghazi arose from a demonstration against an anti-Islamic film made in California. She has said she was using "talking points" provided by the intelligence community.
The administration has since said the attack was a planned act of terror.
Responding to Republican questions, Clinton told the Senate Foreign Relations Committee: "People have accused Ambassador Rice and the administration of misleading Americans. ... Nothing could be further from the truth."
When Sen. Ron Johnson, R-Wis., accused Clinton and the administration of misleading the public on what motivated the attack, Clinton answered with a raised voice: "With all due respect, the fact is we had four dead Americans. Was it because of a protest or was it because of guys out for a walk last night who decided to 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, senator."
She said State Department officials in Washington held off interviewing U.S. evacuees from Benghazi to avoid interfering with the FBI, which was talking to the evacuees as part of an investigation. She said the FBI was "following some very important leads" about who participated in the Benghazi attack.
Clinton told the panel the administration did not know "until days after the attack" that there had been no demonstration. Investigators are still trying to pin down the exact events, she said.
Clinton also told the panel she could not confirm terrorists killed in Algeria were involved in the Libyan attack.
"This information is coming from the Algerian government related to their questioning of certain of the terrorists that they took alive," she said. "We don't have any way to confirm it as yet, but I can certainly assure you, we will do everything we can to determine that.
"You may know that [FBI] Director [Robert] Mueller was just in the region meeting with leaders. He's very well aware that we have to track every one of these connections. And this will be a new thread that will be followed."
The attack on an Algerian gas plant last week left at least 37 foreign hostages dead, Algerian officials said. Algerian forces killed at least 29 of the 32 kidnappers to end the hostage crisis.
Clinton told the Senate panel she did not see requests for extra security in Libya prior to the Sept. 11 attack. She said she did not deny any requests, and procedures were being put in place that any future secretary would see such security messages.
Clinton's voice broke with emotion as she talked about the families of the victims of the Benghazi consulate attack.
"I directed our response from the State Department," she told the panel.
Citing an administrative review board report, she said there were "no delays in decision-making, no denials of support from the Pentagon or the administration ... the board said our response saved lives and it did."
She also stressed that on the day of the attack, "In that same period, we were seeing violent attacks on our embassies" across North Africa. She cited a demonstration in Cairo in which protesters were trying to climb over the U.S. Embassy walls.
Clinton said the United States must still be represented in dangerous places.
"Let me underscore the importance of the United States continuing to lead in North Africa and around the world," she said. "That is why I sent Chris Stevens to Libya. ... He knew the risks ... [but] they cannot work in bunkers and do their jobs. That's why we must do everything possible" to give them security.
Clinton also said the attack didn't happen in a vacuum, citing the problems created within the security apparatus of the region caused by the various government revolutions.
Clinton, her voice breaking, said to her the attack was personal, noting she stood beside President Barack Obama as the caskets of the four people killed in the attack, including Stevens, were returned to the United States.