WASHINGTON - In the months leading up to his death, Chris Stevens, the U.S. ambassador to Libya, worried about constant security threats in Benghazi and mentioned that his name was on an al Qaeda hit list, a source familiar with his thinking told CNN.
Stevens spoke about a rise in Islamic extremism and al Qaeda's growing presence in Libya, the source said.
Matthew Olsen, director of the U.S. National Counterterrorism Center, said it is unlikely that Stevens and his security team were killed by random protesters.
"I would say yes, they were killed in the course of a terrorist attack on our embassy," Olsen said Wednesday at a Senate Homeland Security Committee hearing.
Stevens and three other Americans were killed September 11 during a large protest at the U.S. Consulate in Benghazi. Demonstrators were angry about a film made in the United States that mocked the Muslim Prophet Mohammed.
Sources tracking militant Islamist groups in the region said that a pro-al Qaeda group was the chief suspect and that the attack appeared to have been planned. The attackers used the protest as a diversion, the sources said.
Libyan and U.S. officials are attending a memorial service Thursday in Tripoli for the four Americans.
Washington tried to distance itself from the uproar, making it clear that it did not sanction the film. But more than a week of protests have rippled from Morocco to Malaysia, spurring U.S. officials to increase security at diplomatic missions and demand other governments to take action.
Here are some of the latest key developments in the fallout from the anti-Islam film and from cartoons published in a French satirical magazine featuring a figure resembling Mohammed:
Anti-U.S. protests in Afghanistan, Pakistan
Hundreds of protesters took part in a rally in Kabul, Afghanistan.
They chanted, "Long live Islam, death to America," and "Mohammed is our messenger."
In Islamabad, Pakistan, protesters demonstrated outside the diplomatic enclave that houses foreign embassies, including the U.S. and French embassies.
As many as 1,500 took part, slamming the anti-Islamic movie and the subsequent publishing of satirical cartoons depicting the Mohammed in a French magazine.
Police used tear gas and fired warning shots into the air to disperse the crowd.
Islamabad Police Chief Bin Yamin said some protesters clashed with police, leaving eight police injured.
It was not immediately clear how many protesters were injured.
The demonstration began with a small group of protesters, who were joined by a larger rally organized by Sipah-e-Sahaba, a banned hard-line Sunni Islamist group that's fiercely anti-Shia, Yamin said.
The protest later dispersed, he said.
Also Thursday, Iranian demonstrators gathered in Tehran's Palestinian Square to protest the anti-Islamic film, shouting slogans against the United States and Israel and "those who insulted the holy prophet," said the state-run Iranian news agency IRNA.
Anti-France protests in Iran
Iranian students also demonstrated in front of the French Embassy in Tehran on Thursday, the semiofficial FARS news agency reported.
The protest came a day after the French satirical magazine Charlie Hebdo added to the fiery debate between freedom of expression and offensive provocation.
The magazine known for outrageous humor published cartoons featuring a figure resembling Mohammed.
So far, there has been no violence reported as a result of the Charlie Hebdo cartoons.
Still, France will close embassies and schools in about 20 countries Friday, the main Muslim day of prayer, as a precaution, the French Foreign Ministry said.
It is already boosting security in some locations, including its embassies, and police vehicles were parked outside the Paris offices of Charlie Hebdo earlier this week.
In the past, Muslims in many countries have taken to the streets after Friday prayers.
Any depiction of Islam's prophet is considered blasphemy by many Muslims. France has the largest Muslim population in Western Europe, with an estimated 4.7 million followers of the faith.
The Charlie Hebdo cartoons are not labeled Mohammed, but several, including one that appears to show a man's naked rear end, could easily be interpreted as being depictions of Islam's prophet.
On Thursday, the Paris prosecutor's office said a group called the Syrian Association of Freedom filed a complaint against the magazine for inciting hatred. The magazine turned to the prosecutor's office, asking for an inquiry after its website was hacked.
German magazine may add to debate
Meanwhile, the German satirical magazine Titanic will publish an issue lampooning Islamophobia next week, with a depiction on its cover that could be interpreted as being Mohammed.
Staffer Martina Werner said the Titanic issue will take on film and politicians
making political capital on Islamophobia with a cover from an old movie poster.
Asked if it is supposed to depict Mohammed, Werner answered: "Well, that lies in the eye of the beholder."
Capitol Hill briefings
The White House will roll out top officials Thursday to brief members of the House and Senate about the violent developments across the Middle East and Afghanistan.
Secretary of State Hillary Clinton, intelligence chief James Clapper and members of the Joint Chiefs of Staff will be on hand for the briefing.
"Innocence of Muslims" was an obscure Internet video until September 11 when rioters, seizing on it, breached the U.S. Embassy in Cairo. Protesters also attacked the U.S. Consulate in Benghazi. The film mocks Mohammed as a womanizer, child molester and killer.
Libya has taken steps to arrest those responsible for the consulate attack, bringing in dozens for questioning over the weekend, Libyan officials have said.
The exact number of arrests was unclear. One Libyan official said those arrested included suspects from Mali and Algeria as well as al Qaeda sympathizers.
In recent days, protests against the film have been on the wane, but thousands turned out for a demonstration in Beirut, Lebanon, on Wednesday, waving Hezbollah flags and yelling, "America is an enemy of God." The United States considers Hezbollah a terrorist organization.
Rushdie bounty raised
Amid the unrest, an Iranian imam in a little-known organization has raised the bounty on British novelist Salman Rushdie to $3.3 million -- a half-million-dollar increase.
Rushdie has effectively been under an Islamic death sentence since 1989 when Ayatollah Ruhollah Khomeini of Iran first issued a fatwa after Rushdie's book "The Satanic Verses" was declared blasphemous and sparked protests throughout the Muslim world.
"The death sentence issued against Salman (Rushdie) was meant to dry the roots of anti-Islamic plots, and now by carrying out that sentence the sequence of these anti-Islamic plots could be uprooted and these days are the best time to do that," Hojatoleslam Hassan Sanei said, according to Iran's Mehr News Agency.
Rushie's new book, "Joseph Anton: A Memoir," is an account of the firestorm surrounding "The Satanic Verses" and the death threats against him.
Sanei's organization, the 15th of Khordad Foundation, made news when it first offered a bounty for Rushdie, but in recent years it has fallen out of the public eye.
In Los Angeles, one of the actresses who appeared in "Innocence of Muslims" is suing the producer of the film, Nakoula Basseley Nakoula, claiming she is a victim of fraud, invasion of privacy and misappropriation of her likeness.
Cindy Lee Garcia filed a 17-page complaint in Los Angeles Superior Court on Wednesday, which also names YouTube, the video sharing website on which the video is posted, and its parent company, Google.
Garcia said Google caused her irreparable harm by refusing to remove the content from its site.
Last week, Garcia told CNN she had been unaware the filmmaker dubbed over the dialogue in the movie and inserted anti-Islam sentiments.
The producer's representations that he "intended to make an 'adventure film' and that plaintiff would be depicted as a concerned mother, were false," the suit alleges.
"Defendant ... made an anti-Islam propaganda film, in which plaintiff is falsely made to appear to accuse the founder of the Islamic religion of being a sexual deviant and child molester."
"Ms. Garcia has lost her job, her privacy, and has suffered extreme distress over Nakoula's acts," according to the lawsuit.
According to the complaint, YouTube privately informed Garcia it will not voluntarily remove the content of the video. Attorney M. Cris Armenta said that on Thursday, she will seek an emergency temporary restraining order against Nakoula and YouTube, asking that the content be removed permanently.
Garcia said that she has received death threats and has been unable to visit her grandchildren out of fear that they will be harmed.
Calls to representatives of Nakoula were not immediately returned.
YouTube responded to CNN inquiries, saying it was reviewing the complaint.
CNN's Ed Payne, Josh Levs, Reza Sayah, Ben Brumfield, Hamdi Alkhshali, Jethro Mullen, Shirzad Bozorgmehr and Amir Ahmed contributed to this report.