(CNN) -- Questions surrounding the September 11, 2012, attack on the U.S. diplomatic compound in Benghazi, Libya, that killed Ambassador Christopher Stevens and three other Americans were in the spotlight again on Capitol Hill.
Here's a look at notable comments made by administration officials, publicly and in interviews with CNN, since the attack:
September 12 -- President Barack Obama
"The United States condemns in the strongest terms this outrageous and shocking attack. ... No acts of terror will ever shake the resolve of this great nation."
September 12 -- Secretary of State Hillary Clinton
"We are working to determine the precise motivations and methods of those who carried out this assault. Some have sought to justify this vicious behavior, along with the protest that took place at our embassy in Cairo yesterday, as a response to inflammatory material posted on the Internet. America's commitment to religious tolerance goes back to the very beginning of our nation. But let me be clear: There is no justification for this; none."
September 12 -- White House spokesman Jay Carney, in response to questions about whether the attack was planned
"It's too early for us to make that judgment. I think -- I know that this is being investigated, and we're working with the Libyan government to investigate the incident. So I would not want to speculate on that at this time."
September 12 -- Obama, at a campaign event in Las Vegas, again says "act of terror"
"No act of terror will dim the light of the values that we proudly shine on the rest of the world, and no act of violence will shake the resolve of the United States of America."
He repeats the line again the next day in Golden, Colorado. "I want people around the world to hear me: To all those who would do us harm, no act of terror will go unpunished."
September 13 -- Jay Carney
"The protests we're seeing around the region are in reaction to this movie. They are not directly in reaction to any policy of the United States or the government of the United States or the people of the United States."
September 13 -- A senior U.S. official tells CNN the Benghazi violence was a "clearly planned attack"
"It was not an innocent mob," the official said. "The video or 9/11 made a handy excuse and could be fortuitous from their perspective, but this was a clearly planned military-type attack."
September 13 -- State Department spokeswoman Victoria Nuland
"Well, as we said yesterday when we were on background, we are very cautious about drawing any conclusions with regard to who the perpetrators were, what their motivations were, whether it was premeditated, whether they had any external contacts, whether there was any link, until we have a chance to investigate along with the Libyans. So I know that's going to be frustrating for you, but we really want to make sure that we do this right and we don't jump to conclusions. That said, obviously, there are plenty of people around the region citing this disgusting video as something that has been motivating."
September 14 -- Jay Carney
"We were not aware of any actionable intelligence indicating that an attack on the U.S. mission in Benghazi was planned or imminent."
September 16 -- Susan Rice, U.S. ambassador to the United Nations, on CNN's "State of the Union" with Candy Crowley
"There was a hateful video that was disseminated on the Internet. It had nothing to do with the United States government, and it's one that we find disgusting and reprehensible. It's been offensive to many, many people around the world. That sparked violence in various parts of the world, including violence directed against Western facilities including our embassies and consulates."
On CBS' "Face the Nation," Rice also said that, "We do not have information at present that leads us to conclude that this was premeditated or preplanned."
September 18 -- Jay Carney
"Our belief, based on the information we have, is it was the video that caused the unrest in Cairo, and the video and the unrest in Cairo that helped -- that precipitated some of the unrest in Benghazi and elsewhere. What other factors were involved is a matter of investigation."
September 19 -- Jay Carney
"It is a simple fact that there are, in post-revolution, postwar Libya, armed groups, there are bad actors hostile to the government, hostile to the West, hostile to the United States. And as has been the case in other countries in the region, it is certainly conceivable that these groups take advantage of and exploit situations that develop, when they develop, to protest against or attack either Westerners, Americans, Western sites or American sites. ... Right now, I'm saying we don't have evidence at this point that this was premeditated or preplanned to coincide on a -- to happen on a specific date or coincide with that anniversary."
September 19 -- Matthew Olson, director of the National Counterterrorism Center, responding to a question by Senate Homeland Security Committee Chairman Joe Lieberman on whether Benghazi was a terrorist attack
"They were killed in the course of a terrorist attack on our embassy. ... At this point, what I would say is that a number of different elements appear to have been involved in the attack, including individuals connected to militant groups that are prevalent in eastern Libya, particularly the Benghazi area, as well we are looking at indications that individuals involved in the attack may have had connections to al Qaeda or al Qaeda affiliates, in particular al Qaeda in the Islamic Maghreb." Olson also said U.S. officials had no "specific evidence of significant advanced planning."
September 20 -- Jay Carney
"It is, I think, self-evident that what happened in Benghazi was a terrorist attack. Our embassy was attacked violently, and the result was four deaths of American officials."
September 20 -- President Obama at a town hall meeting organized by the Spanish-language Univision Network, responding to a question about the possible involvement of al Qaeda
"What we do know is that the natural protests that arose because of the outrage over the video were used as an excuse by extremists to see if they can also directly harm U.S. interests."
September 21 -- Hillary Clinton
"What happened in Benghazi was a terrorist attack and we will not rest until we have tracked down and brought to justice the terrorists who murdered four Americans."
September 25 -- President Obama on ABC's "The View," in response to interviewer Joy Behar's question, "I heard Hillary Clinton say it was an act of terrorism. Is it? What do you say?"
"We're still doing an investigation. There's no doubt that (with) the kind of weapons that were used, the ongoing assault, that it wasn't just a mob action. We don't have all the information yet, so we're still gathering it. But what's clear is that around the world, there's still a lot of threats out there." Obama also said "extremist militias" were suspected to have been involved.
September 26 -- Hillary Clinton
"What is happening inside Mali is augmented by the rising threat from violent extremism across the region. For some time, al Qaeda in the Islamic Maghreb and other groups have launched attacks and kidnappings from northern Mali into neighboring countries. Now, with a larger safe haven and increased freedom to maneuver, terrorists are seeking to extend their reach and their networks in multiple directions. And they are working with other violent extremists to undermine the democratic transitions under way in North Africa, as we tragically saw in Benghazi."
September 27 -- Secretary of Defense Leon Panetta
"It was a terrorist attack. ... As we determined the details of what took place there and how that attack took place, it became clear that there were terrorists who had planned that attack."
September 27 -- A senior U.S. official tells CNN that it became clear within about a day of the Benghazi attack that it been the work of terrorists
Separately, CNN National Security Analyst Fran Townsend reports that a law enforcement source told her that "from day one, we had known clearly that this was a terrorist attack."
September 28 -- Statement by Shawn Turner, spokesman for Director of National Intelligence James Clapper
"In the immediate aftermath, there was information that led us to assess that the attack began spontaneously following protests earlier that day at our embassy in Cairo. We provided that initial assessment to executive branch officials and members of Congress, who used that information to discuss the attack publicly and provide updates as they became available. Throughout our investigation, we continued to emphasize that information gathered was preliminary and evolving. As we learned more about the attack, we revised our initial assessment to reflect new information indicating that it was a deliberate and organized terrorist attack carried out by extremists."
October 1 -- Nuland, in response to calls from Rep. Peter King, R-California, for Rice to resign because her remarks about the attack were, according to him, misleading
"Well, let me start by saying that Secretary Clinton believes that Ambassador Rice has done a superb job. So let's just start there, and we completely reject any such calls here in this building."
October 1 -- Nuland, responding to a question about whether officials in Libya had sought additional security for diplomatic installations and personnel there
"I think it's fair to say that we are still working through what we have in this building in terms of documentation, in terms of information about what we knew, who knew it, when they knew it, and that's part of the process that we have to go through."
October 2 -- Carney
"I can tell you that from the moment our facility was attacked in Benghazi, the president's focus has been on securing our diplomats and facilities in Libya and around the world, and on bringing the killers to justice. At every step of the way, the administration has based its public statements on the best assessments that were provided by the intelligence community. As the intelligence community learned more information, they updated Congress and the American people on it."
October 9 -- During a background briefing with reporters, a senior State Department official responding to a question about whether the attack was a spontaneous assault taking advantage of a demonstration over the movie
"That is a question that you would have to ask, have to ask others. That was not, that was not our conclusion. I'm not saying that we had a conclusion."
The background briefing contains detailed information about the attack, including how dozens of armed men stormed the complex as Stevens and two security team members took refuge in a fortified room.
"The lethality and the number of armed people is unprecedented," one official said. "There had been no attacks like that anywhere in Libya -- Tripoli, Benghazi or anywhere -- in the time that we had been there. And so it is unprecedented, in fact, it would be very, very hard to find precedent for an attack like (it) in recent diplomatic history."
October 9 -- Clapper, during a speech in Orlando
Upon returning from a trip to Australia, Clapper said, he was "reading the media clips about the hapless, hopeless, helpless, inept, incompetent DNI, because I acknowledged publicly that we didn't instantly have that 'God's eye, God's ear' certitude" about what had happened.
He later added, in answer to a question: "The challenge is always a tactical warning, the exact insights ahead of time that such an attack is going to take place, and obviously we did not have that. This gets into the mysteries versus secrets thing. If people don't behave, emit a behavior or talk or something else ahead of time to be detected, it's going to be very hard to predict an exact attack and come up with an exact attack."
October 10 -- Under Secretary of State for Management Pat Kennedy, in congressional testimony
"No one in the administration has claimed to know all the answers. We have always made clear that we are giving the best information we have at the time, and that information has evolved."
In the same hearing, Deputy Assistant Secretary of State for International Programs Charlene Lamb testified that the State Department "had the correct number of assets in Benghazi at the time."
October 10 -- Obama, in an ABC interview
"The information may not have always been right the first time. And as soon as it turns out that we have a fuller picture of what happened, then that was disclosed."
October 10 -- Carney, responding to questions about whether administration officials had misled the public because they did not want to acknowledge a terrorist attack
"The president of the United States referred to it as an act of terror immediately after it occurred."
"I never said we don't know if it's terrorism. There was an issue about the definition of terrorism. This is by definition an act of terror, as the president made clear."
October 11 -- Vice President Joe Biden, during his debate with GOP vice presidential candidate Paul Ryan, responding to a question about what the administration knew about security requests from Libya.
"We weren't told they wanted more security there."
October 12 -- Carney, asked to respond to Biden's comments
"The vice president was speaking about himself, and the president and the White House. He was not referring to the administration, clearly, since there was a public hearing for four and a half hours where it was discussed openly by individuals working at the State Department requests that were made."
October 15 -- Clinton, in an interview with CNN
"I take responsibility. I'm in charge of the State Department's 60,000-plus people all over the world, 275 posts. The president and the vice president wouldn't be knowledgeable about specific decisions that are made by security professionals. They're the ones who weigh all of the threats and the risks and the needs and make a considered decision."
October 16 -- Obama, speaking to GOP challenger Mitt Romney at their second debate
"The day after the attack, governor, I stood in the Rose Garden and I told the American people in the world that we are going to find out exactly what happened; that this was an act of terror. And I also said that we're going to hunt down those who committed this crime."
"I am ultimately responsible for what's taking place there because these are my folks, and I'm the one who has to greet those coffins when they come home."
October 18 -- Obama talking to Jon Stewart on Comedy Central's "The Daily Show"
"The government is a big operation and any given time, something screws up. And you make sure that you find out what's broken and you fix it."
"When four Americans get killed, it's not optimal. We're going to fix it. All of it."
When Stewart asked about "confusion" over the Benghazi attack, the president laid out what he learned from the situation.
"(We) weren't confused about the fact that four Americans had been killed. I wasn't confused about the fact that we needed to ramp up diplomatic security around the world right after it happened. I wasn't confused about the fact that we had to investigate exactly what happened so it gets fixed. And I wasn't confused about the fact that we're going to hunt down whoever did it."
October 19 -- Several senior administration officials tell CNN that UN Ambassador Susan Rice's use of the word "spontaneous" was a poor word choice
Several officials say instead of calling it "spontaneous," it might have been better phrased as: the attack had not been long planned, or there were no signs of an upcoming attack on September 11. Rice relied on talking points provided by the CIA that were not edited by the White House.
October 24 -- CNN obtains e-mails showing evidence that the White House knew of extremist claims in Benghazi attack
Two hours after the attack on the U.S. diplomatic compound in Benghazi, the White House, the State Department and the FBI were told that an Islamist group had claimed credit, government e-mails obtained by CNN show.
One of the e-mails -- sent from a State Department address to various government agencies -- specifically identifies Ansar al-Sharia as claiming responsibility for the attack on its Facebook page and on Twitter.
The e-mails raise further questions about the seeming confusion on the part of the Obama administration to determine the nature of the September attack and those who planned it.
October 24 -- Hillary Clinton on e-mails
"The Independent Accountability Review Board is already hard at work looking at everything, not cherry picking one story here or one document there but looking at everything, which I highly recommend as the appropriate approach to something as complex an attack like this.
"You know, posting something on Facebook is not in and of itself evidence. I think it just underscores how fluid the reporting was at the time and continued for some time to be."
October 24 -- Jay Carney noted the e-mail about the claim of responsibility
"Was an open-source, unclassified e-mail referring to an assertion made on a social media site that everyone in this room had access to and knew about instantaneously.
"The whole point of an intelligence community and what they do is to assess strands of information and make judgments about what happened and who was responsible."
November 1 -- Intelligence official offers new timeline for Benghazi attack
A senior U.S. intelligence official emphatically denied that the CIA refused repeated requests from its officers on the ground in Benghazi to assist the Americans under attack at the mission.
The official offered almost a minute-by-minute account of what happened that night.
November 9 -- Timeline released
The Pentagon released an hour-by-hour timeline of the September 11 assault, highlighting when Defense Secretary Leon Panetta and senior commanders were informed of the attack and when decisions were made to move forces to assist.
November 15 -- Benghazi hearing takes place
Republicans and Democrats attended closed-door sessions of the House and Senate intelligence committees. They vowed to keep asking questions and keep holding hearings to determine not only how Ambassador Christopher Stevens and three other Americans died, but also whether officials were forthright in the attack's aftermath.
November 16 -- Former CIA Director David Petraeus testified on Capitol Hill
Petreaus said that the attack was an act of terrorism committed by al Qaeda-linked militants.
November 19 -- Official: Changes to Benghazi talking points made by intelligence community
The intelligence community -- not the White House, State Department or Justice Department -- was responsible for the substantive changes made to the talking points distributed for government officials who spoke publicly about the attack on the U.S. mission in Benghazi, the spokesman for the director of national intelligence said.
December 14 -- Susan Rice withdraws from consideration as secretary of State
After heavy criticism from Republicans over her statements after the attacks, Rice withdrew her name from consideration for secretary of state.
In a letter to President Barack Obama, she said "the confirmation process would be lengthy, disruptive, and costly -- to you and to our most pressing national and international priorities. That trade-off is simply not worth it to our country."
January 23 -- Hillary Clinton
"We continue to hunt the terrorists responsible for the attacks in Benghazi and are determined to bring them to justice.
"There's evidence that the attacks were deliberate, opportunistic and precoordinated but not necessarily indicative of extensive planning."
January 29 -- Hillary Clinton on CNN
Asked in a CNN interview why she didn't "connect the dots" about some of the security threats that existed in Libya before the attack, Clinton said those threats were considered "manageable" by the State Department's evaluation and security professionals.
"We have a lot of (threats) around the world. I mean there is a long list of attacks that have been foiled, assassination plots that have been prevented, so this is not some one-off event. This is considered in an atmosphere of a lot of threats and dangers, and at the end of the day, there was a decision made that this would be evaluated but (the Consulate) would not be closed, and, unfortunately, we know what happened."
February 3 -- Leon Panetta to CNN: Benghazi an intel failure
Outgoing Defense Secretary Leon Panetta told CNN's Candy Crowley that he had little warning that an attack on the Benghazi compound was imminent. "That's just the nature of dealing with the Middle East," he said. "We've learned some lessons, obviously, from what happened in Benghazi."
April 18 -- John Kerry: Let's move on
Secretary of State John Kerry told lawmakers he suggested were harping on the Obama administration's response to the Benghazi attacks: Let's move on.
"Let's get this done with, folks," Kerry told the House Foreign Affairs Committee in his first appearance before Congress after taking office. "I do not want to spend the next year coming up here talking about Benghazi."
May 6 — Diplomat raises concerns
Greg Hicks, a former top diplomat in Libya, said he expressed concern that more could have been done by the military to protect those under attack at the main U.S. compound and annex in Benghazi. Hicks wondered why the military did not send a plane into Libyan airspace as a show of force, and why four U.S. Special Operations soldiers were not permitted to travel to Benghazi on a Libyan plane the morning after the attack.
May 8 -- Republicans and Democrats tangle
The House Oversight Committee hearing featured a riveting account of the Benghazi assault by Gregory Hicks that included his last phone call with Stevens in which the ambassador told him "We're under attack." Hicks, one of three "whistleblowers" who testified, was joined by Mark Thompson and Eric Nordstrom. Hicks said his "jaw dropped" when he heard Susan Rice tie the attack to a spontaneous demonstration, which he said never occurred to his knowledge. Democrats and Republicans tangled over the fierce partisan politics surrounding the attack with one lawmaker accusing the Obama administration of covering up events. Democrats blasted the GOP for politicizing a tragedy. Jay Carney defended the administration's handling of the attacks, saying it had "made extraordinary efforts to work with" Congress on multiple investigations.
May 9 -- Kerry vows to get answers
Secretary of State John Kerry vowed to "leave no stone unturned" in looking into Benghazi and the subsequent handling of the matter. Speaking in Rome, Kerry said he was determined to get answers to questions and put the issue "to bed." "And if there is any culpability in any area that is appropriate to be handled in some way with some discipline it will be appropriately handled."
CNN's Adam Aigner-Treworgy, Elise Labott, Julie In, Diane Laposta, Adam Levine, Alyssa McLendon and Tom Dunlavey contributed to this report.