-- In Gaza City, Palestinians demonstrated outside U.N. headquarters, and about 200 Palestinians protested the film at the Palestine Legislative Council building. In one instance, Palestinian men burned a U.S. flag.

-- In Tel Aviv, Israel, about 50 people demonstrated in front of the U.S. Embassy.

-- In Sudan, the United States called on U.S. citizens Wednesday to stay away from the embassy in Khartoum, where protests were going on.

-- Iranians protested near the Swiss Embassy in Tehran on Thursday. Switzerland represents U.S. interests in Iran, since Washington and Tehran do not have diplomatic relations. Up to 500 people chanted "Death to America!" and called for death to the director of the movie, which was made in the United States. The demonstration ended peacefully after two hours.

The Islamic Propagation Coordination Council, meanwhile, has issued a statement calling for rallies across Iran on Friday "to protest Zionist-U.S. plots against Muslim and Islamic values," the state-run IRNA news agency reported.

-- In Iraq, specifically in the predominantly Shiite area of eastern Baghdad known as Sadr City, hundreds of protesters hit the streets to protest the film. They chanted, "America is the enemy of the people," with some burning an American flag and others putting one on the ground and stomping on it. Other followers of radical cleric Muqtada al-Sadr also protested in the provinces of Najaf and Karbala.

So far, the violence has not spread to Afghanistan, where there is a high potential for outrage to erupt into destabilizing chaos. Obama and his Afghan counterpart, Hamid Karzai, have expressed their commitment to prevent that from happening.

FBI reaches out to anti-Islam filmmaker

As questions swirl about the film at the center of the ongoing protests, U.S. officials stepped up their criticism of the video, which was privately produced in the United States, and began pursuing the elusive filmmaker who allegedly made it.

Clinton said Thursday of the video: "It appears to have a deeply cynical purpose, to denigrate a great religion and to provoke rage. But as I said yesterday, there is no justification, none at all, to responding to this video with violence. We condemn the violence that has resulted in the strongest terms. And we greatly appreciate that many Muslims in the United States and around the world have spoken out on this issue."

The FBI has spoken to the filmmaker within the past 24 hours, a federal law enforcement officer told CNN on Thursday.

Feinstein, head of the U.S. Senate Intelligence Committee, said she believes "an investigation is going on in this country considering the individual who did this very obnoxious ... preview to some very stupid movie and wrong-headed movie."

Many Muslims find any depiction of Mohammed to be offensive -- a Danish newspaper's publication in 2005 of Mohammed caricatures triggered riots -- and derogatory depictions of the prophet are considered by some to be worse.

The Afghan government has ordered an indefinite block of YouTube to prevent people there from watching the clips and staging violent protests. YouTube has already restricted access to the video.

A production staffer on the film said the filmmaker was a Coptic Christian who had gone to Alexandria, Egypt, where the Coptic church is based, to raise money for the film. Far from standing behind the film, the Coptic church has issued a statement calling it "abusive" and part of a "malicious campaign to divide people."

Response to ambassador's killing

Sources tracking militant Islamist groups in eastern Libya say Tuesday night's deadly attack was most likely carried out by a pro-al Qaeda group. Obama has vowed that "justice will be done."

U.S. warships, carrying guided missiles, are on their way to the coast of Libya, and unmanned drones are being sent to help search for the killers.

A group of Marines called a Fleet Antiterrorism Security Team was deployed to Libya to help secure U.S. facilities, two U.S. officials said. About 50 Marines arrived in the country Wednesday, officials said.

Libyan Prime Minister Abushagur said he is heading a high-level commission that includes heads of the North African nation's foreign, defense and interior ministries to investigate the attack.

"Our friends ... have supported us throughout these difficult times," he said of the U.S. government. "We are very determined to bring things back to order."

Abushagur said that the arrests made, and sought, in Libya followed examination of video from the scene in Benghazi and statements from witnesses.

U.S. political fallout

The events have shifted the U.S. presidential race to a focus on foreign policy, with Republican nominee Mitt Romney repeatedly criticizing the responses by Obama and his administration.

At a Virginia rally Thursday, Romney said, "As we watch the world today, sometimes it seems that we're at the mercy of events instead of shaping events, and a strong America is essential to shape events."