So far, there has been no evidence of a direct role by al-Qaida in the protests.
U.S. and Libyan officials are investigating whether the protests were a cover for militants, possibly al-Qaida sympathizers, to carry out a coordinated attack on the U.S. Consulate in Benghazi and kill Americans. Washington has deployed FBI investigators to try and track down militants behind the attack.
The United States sent an elite, 50-member Marine unit to Yemen’s capital to bolster security at the embassy there, which protesters broke into on Thursday and then tried again to assault Friday. A similar team was dispatched to Tripoli, Libya, on Wednesday after the deadly attack the night before on the Benghazi consulate.
But the Sudanese government said Saturday it had refused to allow a similar Marine deployment to the embassy in Khartoum. Sudanese Foreign Minister Ali Karti declined the request, saying Sudan is capable of protecting diplomatic missions, the state news agency said.
State Department spokeswoman Victoria Nuland said Sudan’s government ‘‘has recommitted itself both publicly and privately to continue to protect our mission.’’ She said the U.S. has requested additional security precautions.
Later in the day, the State Department issued a travel warning for Sudan and Tunisia, ordering home non-essential personnel and family members of staff at posts in both countries over security concerns.
The department added that while Sudan’s government has taken steps to limit the activities of terrorist groups, some remain there and have threatened to attack Western interests. The terrorist threat level remains critical, it said.
Elsewhere in the region, security was increased Saturday at several spots that had been targeted.
Police in Lebanon beefed up their presence around U.S. fast food restaurants Saturday, after angry crowds Friday set fire to a KFC and a Hardee’s restaurant in the port city of Tripoli. In Tunisia, the U.S. Embassy compound and school were surrounded by police and army vehicles Saturday.
The protests were sparked by an obscure, amateurish movie called ‘‘Innocence of Muslims’’ that depicts Muhammad as a fraud, a womanizer and a pedophile. A 14-minute ‘‘trailer’’ for the movie, dubbed into Arabic, was posted on YouTube.
The top religious authority in Saudi Arabia, Grand Mufti Sheik Abdel-Aziz al-Sheik, condemned the movie on Saturday but said it ‘‘will not harm’’ Islam or Muhammad.
‘‘Muslims should not be dragged by wrath and anger to shift from legitimate to forbidden actions. By this, they will unknowingly fulfill some aims of the film,’’ he said.
The head of al-Azhar, Sheik Ahmed al-Tayeb, called on the United Nations to take a stand against hate speech, pointing out that the world body has done so in defense of Jewish people.
He said that while defending the Prophet Muhammad is a duty for all Muslims — it should be ‘‘not only through peaceful protests ... but also through reviving his teachings in all walks of life and spreading his moderate ideas.’’
In the U.S., the man behind the movie was questioned at a California sheriff’s station early Saturday by federal probation officers investigating whether he had violated terms of his five-year probation. Nakoula Basseley Nakoula wasn’t arrested or detained.
Federal authorities have identified Nakoula, a self-described Coptic Christian, as the key figure behind the film. A federal law enforcement official told The Associated Press on Thursday that authorities had connected Nakoula to a man using the pseudonym of Sam Bacile, who claimed earlier to be writer and director of the film.
Nakoula was convicted of bank fraud in 2010 and is banned from using the computers and the Internet as part of his sentence.
Contributing to this report were Sarah El-Deeb in Cairo, Bouazza ben Bouazza in Tunisia and Jim Kuhnhenn in Washington.