Comments by U.S. officials regarding the September 11 attack that killed four Americans in Benghazi, Libya, have provoked controversy among some critics.

Some Republicans have accused the administration of being less than forthcoming about the causes of the incident, saying the administration has focused on "The Innocence of Muslims," the inflammatory online video mocking the Muslim Prophet Mohamed as the explanation for the attack.

Here's a rundown of notable statements by administration officials, publicly and in interviews with CNN:

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 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 that 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 CBS' "Face the Nation":

"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, post-war 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 -- Director of National Intelligence Matthew Olson, responding to a question by Senate Homeland Security and Governmental Affairs Chairman Joe Lieberman on whether the attack 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."