Washington — The Obama administration was caught by surprise by the ferocity of the 11 September attack against the US Consulate in Benghazi, Libya, that killed the ambassador and three other Americans.
Now it is bracing for another potential eruption of violent demonstrations in parts of the Muslim world after Friday's weekly prayers — traditionally a time of protest in the Middle East and North Africa.
Angry demonstrations over an anti-Islam video already have occurred in Egypt and Yemen, and officials theorise that well-armed Libyan extremists hijacked a similar protest in Benghazi, where several Libyan security guards also were killed.
The US put all of its diplomatic missions overseas on high alert, and Secretary of State Hillary Clinton delivered an explicit denunciation of the video as the administration sought to pre-empt further turmoil at its embassies and consulates.
"The United States government had absolutely nothing to do with this video," she said before a meeting with the foreign minister of Morocco at the State Department. "We absolutely reject its content and message."
"To us, to me personally, this video is disgusting and reprehensible," Clinton said. "It appears to have a deeply cynical purpose: To denigrate a great religion and to provoke rage."
No advance warning
US officials said they suspect that the attack at the Benghazi consulate, which had also been the target of an unsuccessful attack in June, may have been only tangentially related to the film.
They also stressed there had been no advance warning or intelligence to suggest a threat in Libya that would warrant boosting security, even on the 11th anniversary of the terror attacks of 11 September 2001.
"As we did with all of our missions overseas, in advance of the September 11 anniversary and as we do every year, we did evaluate the threat stream and we determined that the security at Benghazi was appropriate for what we knew," State Department spokesperson Victoria Nuland said.
The intelligence leading up to the attacks will be examined to "see if there was any way of forecasting this violence", as in any violent incident, House Intelligence Committee member Adam Schiff, said in an interview on Thursday.
But he said the focus now "has to be on finding out who is responsible and bringing them to justice".
According to a Reuters report, Libyan authorities have since made four arrests in the investigation into the attack on the US consulate in Benghazi on Thursday. The report cited the deputy interior minister.
'Opportunistic or spontaneous'
"Four men are in custody and we are interrogating them because they are suspected of helping instigate the events at the US consulate," Wanis Sharif told Reuters.
He gave no more details.
President Barack Obama, speaking a campaign event in Golden, Colorado, also vowed that the perpetrators would be punished.
"I want people around the world to hear me," he said. "To all those who would do us harm: No act of terror will go unpunished. I will not dim the light of the values that we proudly present to the rest of the world. No act of violence shakes the resolve of the United States of America."
As of Thursday morning, there was no intelligence indicating that what happened in Benghazi was planned, according to two US officials briefed on the investigation into the attack.
Intelligence officials said they believe it's more likely that the attack was "opportunistic or spontaneous", with militants taking advantage of the demonstration to launch the assault.
No ties to 9/11
The officials spoke on condition of anonymity because they were not authorised to discuss the ongoing investigation publicly.
There is also no evidence that the attack was tied to 9/11, one of the officials said.
But the Libyan-based militant group Ansar al Sharia is the leading suspect for carrying out the violence, possibly with help from al-Qaeda's main African-based offshoot, Al-Qaeda in the Islamic Maghreb.
The officials said it may be hard to determine definitively which group was responsible, because many militants are members of both.
Despite the belief that the militants who hit the consulate did so separately from the protests over the film, US officials are deeply concerned that extremists may take advantage of non-violent demonstrations to copycat the Benghazi raid, or that otherwise peaceful protesters may be incited to attack because of the video, particularly on Friday.
It's virtually impossible to predict when a crowd might form and turn violent, according to retired US Ambassador John Negroponte, who served as chief of mission at five posts, including Iraq, and is a former director of national intelligence.
Ban denounces violence
"These things can be mobilised on the spur of the moment, set off by a spark," especially in places such as Egypt and Libya where the ruling strongmen have just fallen, Negroponte said on Thursday.
"When you get rid of authoritarian regimes, there's little or no institutional framework left. ...That's why there's disorder and chaos" that is so easily hijacked, he said.
UN Secretary-General Ban Ki-moon on Thursday denounced the violence, and also the provocative video. "Nothing justifies such killings and attacks," Ban said in a statement, adding that he condemns "the hateful film that appears to have been deliberately designed to sow bigotry and bloodshed".
Egypt's ruling Muslim Brotherhood called for demonstrations after Friday prayers as did authorities in Iran and the Gaza strip.
Large protests were expected in Baghdad and Iraq's second-largest city, Basra, as well as Amman, Jordan. Israel was stepping up security in anticipation of demonstrations after Muslim prayers.
The White House said it was prepared for more protests but stressed that any violence would be unjustified.
No justification: Clinton
"It is important to note that as these protests are taking place in different countries around the world, responding to the movie, that Friday, tomorrow, has historically been a day when there are protests in the Muslim world," White House press secretary Jay Carney told reporters in Colorado.
"And we are watching very closely for developments that could lead to more protests. We anticipate that they may continue."
While rejecting the content of the video, Clinton stressed that no matter how offensive it is, the film cannot be used as an excuse for violence like that seen in Egypt, where a mob breached the walls of the US Embassy in Cairo on Wednesday, and in Yemen, where demonstrators tried to storm the embassy compound in Sana on Thursday.
"There is no justification, none at all, for responding to this video with violence," Clinton said. "We condemn the violence that has resulted in the strongest terms. ... It is especially wrong for violence to be directed against diplomatic missions. These are places whose very purpose is peaceful: To promote better understanding across countries and cultures."
She then reminded foreign governments that they have a responsibility to protect embassies.
Around the world, US missions issued warnings to Americans about demonstrations that could turn violent. More than 50 embassies and consulates have released such alerts since Wednesday, the State Department said.