An investigation will focus on whether the assault on the U.S. Consulate in Libya was a planned terrorist strike to mark the anniversary of the Sept. 11, 2001, attacks and not a spontaneous mob enraged over an anti-Islam YouTube video.
U.S. officials believe the militants were using the demonstration against the video as a cover to get into the consulate and then take as much revenge as they could on Americans.
ALSO: Protestors Forced Back After Rushing Walls of U.S. Embassy in Yemen
While the White House has been hesitant to call the attack planned, House Intelligence Committee Chairman Mike Rogers was not so ambiguous."Absolutely it's a terrorist attack," Rogers told CBS News Capitol Hill producer Jill Jackson. "This was not done by the Libyan government. It was done by an external group we believe has at least extremist ties, maybe al Qaeda ties, and the style and the signature of the attack clearly would be something that we have seen before and would be in line with something al Qaeda would do
White House press secretary Jay Carney said it was too early to judge whether the attack was planned.
"I know that this is being investigated, and we're working with the Libyan government to investigate the incident. I would not want to speculate on that at this time," he said. Several Libyan security guards also were killed.
Rogers, R-Mich., said U.S. intelligence had not yet determined who was responsible, but added, "Our list is narrowing."
"When you see (such an attack), it wasn't some folks who had some guns in their garage and said let's shoot up the consulate," Rogers said.
Analysts are working on several different scenarios based on intelligence that could lead to a motive for the attack. Some concern the possibility of targeting high-ranking officials, according to a law enforcement official briefed on the investigation.
But none of the intelligence thus far has suggested terrorists would specifically target Stevens, said the official who also spoke on condition of anonymity because he was not authorized to speak publicly about the investigation.
The attack in Libya, which came hours after a mob stormed the U.S. Embassy in Cairo and tore down the U.S. flag, was presumed to have been triggered by a movie, whose trailer has gone viral on YouTube, depicting the Islamic prophet Muhammad in disrespectful ways. In an extraordinary move, Gen. Martin Dempsey, the chairman of the Joint Chiefs of Staff, called anti-Islamic preacher Terry Jones and asked him to stop promoting the film. A spokeswoman said the church would not show the film Wednesday evening.
"Make no mistake. Justice will be done," a somber Obama pledged at the White House, Secretary of State Hillary Rodham Clinton at his side.
The Hunt In LIbya...
(CBS/AP) WASHINGTON - The Obama administration, roiled by the first killing of a U.S. ambassador in more than 30 years, has begun what appears to be a terrorist hunt in Libya, as evidence mounts that the deaths of four diplomatic workers there were perpetrated by well-armed thugs and not an out-of-control crowd.
CBS News correspondent David Martin reports the FBI has opened an investigation into the deaths, and agents will be sent to sift through the wreckage for evidence. They will be accompanied by a second team sent just for their protection.
As part of the hunt for the attackers, officials say the U.S. will increase its surveillance over Libya, including the use of unmanned drones. In addition, the U.S. Navy is positioning two destroyers armed with cruise missiles off the coast of Libya.
One destroyer, the USS Laboon, moved to a position off the coast Wednesday, and the USS McFaul is en route and should be stationed off the coast within days. Officials said the ships, which carry Tomahawk cruise missiles, do not have a specific mission. But they give commanders flexibility to respond to any mission ordered by the president.
After the attack, an elite anti-terrorist unit of about 40 Marines was flown in to beef up security at the American embassy in the capital of Tripoli. Air Force transport planes flew the bodies of the dead Americans out, along with at least three who were injured and the rest of the approximately 25 diplomats assigned to the consulate. At the same time, the U.S. State Department urged all non-essential personnel to leave on commercial flights.
Three Americans injured in the assault on the consulate in Benghazi were being treated Thursday at the U.S. military hospital in Landstuhl, Germany, near America's Ramstein Air Base, CBS News has learned.
Wanis al-Sharef, a Libyan Interior Ministry official in Benghazi, said there had been threats that Islamic militants might try to take revenge for the death of al Qaeda's No. 2 commander Abu Yahya al-Libi, who was killed in a U.S. drone strike in Pakistan in June, and he said the U.S. consulate should have been better protected.
Confirming al-Libi's death for the first time in a video posted online Monday, al Qaeda chief Ayman Al-Zawahri called on Muslims in al-Libi's native Libya to take revenge for his death.n for violence against innocents."
Protestors Forced Back After Rushing Walls of U.S. Embassy in Yemen
(CBS News) LONDON - There were clashes Thursday between anti-U.S. protesters and Yemeni police at the U.S. Embassy in Sanaa. CBS News sources say a large group of protesters reached the walled compound, but failed to breach any of the buildings inside the compound as police fired warning shots to try to disperse the crowd.
All U.S. embassies and diplomatic posts were ordered to increase security measures Wednesday by President Obama, following the deadly attack on the U.S. consulate in Benghazi, Libya, on Tuesday.
The number of protesters in Sanaa was estimated between 3,000 and 4,000, according to sources speaking to CBS News partner network Sky News.
Yemen is the home of al Qaeda in the Arabian Peninsula (AQAP), one of the most active and dangerous terror groups linked to the central al Qaeda organization. The U.S. military and intelligence agencies have worked alongside Yemeni officials to counter the Islamic extremist element inside the country. Many drone strikes have been carried out, allegedly by the U.S., in the last year targeting militants in Yemen.
There has been mounting concern among Western security services that AQAP and the al Qaeda franchise in north Africa, al Qaeda in the Islamic Maghreb (AQIM), have been sharing resources.
The clashes at the embassy came as protests continued Thursday outside the U.S. Embassy in Cairo, Egypt - the first location where Muslim anger apparently aimed at a video ridiculing the Islamic prophet Muhammad manifested itself on Tuesday.
CBS News correspondent Holly Williams reports the clashes in Cairo again became violent on Wednesday, as protesters tried to push toward the embassy compound walls. Egyptian riot police used shields and batons to push them back from walls, but resorted to tear gas when the protesters continued advancing.
The crowd eventually thinned out, but Williams says a small group of protesters remained in front of the embassy all night.
Thursday morning there were sporadic clashes again with riot police, who were out in force, possibly expecting bigger crowds later in day.
Williams reports that the clashes in Cairo have caused some tension with the U.S. for Egypt's fledgling democracy, led by President Mohamed Morsi.
Morsi received a call from President Obama Wednesday night, during which Mr. Obama, "underscored the importance of Egypt following through on its commitment to cooperate with the United States in securing U.S. diplomatic facilities and personnel," according to the White House.
That statement from the White House implies the Obama administration was critical of the Egyptian authorities' response to the demonstrations on Tuesday, when protesters breached the embassy compound and managed to tear down and burn the U.S. flag.
CBS News' Alex Ortiz reports that, since Morsi won the recent presidential elections in Egypt with huge support from conservative Muslims, security around the U.S. Embassy in Cairo had been visibly reduced.
Williams says Morsi is now in a difficult position. On the one hand Egypt has been a strong ally to the U.S. in the Middle East, and while those relations have cooled slightly since Morsi and the Muslim Brotherhood rose to power, the ties are still important. The protests at the embassy won't do the relationship any good, and that explains the now heavy presence of riot police.
On the on other hand, however, Morsi knows that his base of support is still with the nation's conservative Muslims, and that explains his government's strong condemnation of the mysterious anti-Muslim video which appeared on Youtube his summer, and which has been the catalyst for the protests in Egypt and elsewhere.
Meanwhile, there was reportedly a warning Thursday from an Iraqi militant group linked to the powerful anti-U.S. Shiite cleric Muqtada al-Sadr, that U.S. interests in Iraq were "in danger" over the movie. The Asaib al-Haq militia, a Shiite group based in Iraq's south, had already urged Iraq's government to ban the video and hold the U.S. responsible for it's production - though it remains unclear whether the movie - if it exists as a full-length film - was even produced in the United States.
While there has been nothing to suggest the U.S. government or any individuals connected to it had anything to do with the production of the vitriolic 15-minute clip on Youtube, which is allegedly a promotion clip for a bigger movie called the "Innocence of Muslims," extremist Muslim groups around the world have been quick to use it as propaganda - suggesting it is the product of what many jihadists believe is an American war on Islam.