* "Can't freak out on everything broadcast"
* Congressional inquiries seen likely
By Mark Hosenball
WASHINGTON, Sept 13 (Reuters) - U.S. officials say they believe an Arabic talk show last Saturday showing parts of an anti-Muslim video made in the United States was the spark that set off violent attacks on U.S. missions in Libya and Egypt, but acknowledge the broadcast did not prompt a major upgrade in security precautions.
On Tuesday, four Americans, including Ambassador Christopher Stevens, were killed in an attack on the American Consulate in Benghazi, Libya, that U.S. officials said may have been planned by one or more militant factions. On the same day, protesters in Cairo breached the U.S. Embassy's walls, and the protests have since spread to other countries, including Yemen, Bangladesh and Kuwait.
An Egyptian TV network, al-Nas, broadcast last Saturday what its presenters described as extracts from an English-language film denigrating the Prophet Mohammad, which it said had been uploaded on the YouTube website by "migrant Coptics," a reference to exiled members of a Christian sect with a large minority presence among Egypt's Muslim majority.
The clips broadcast on al-Nas were taken from a short film available on the Internet. It is called "Innocence of Muslims," and portrays the Prophet - played by what appears to be a young American actor - as a womanizer, thug and child molester.
Three U.S. officials said the broadcast did not prompt strong warnings from intelligence agencies or the State Department of possible threats to U.S. diplomatic missions in the Islamic world.
One official, who like the others spoke on condition of anonymity, said there was at least one specific warning about possible unrest in the region that was circulated within the government, but was not so alarming as to lead to a major upgrade in security for a possible emergency.
The lack of a major upgrade in precautions may show how difficult it is for officials to assess threats that first emerge on social media. The threats can seemingly come out of nowhere and gather strength rapidly.
The events also underline the role of the Middle East's more freewheeling media, loosened from state restrictions after the fall of longtime dictators.
For many Muslims, any depiction of the Prophet is blasphemous, and caricatures or other characterizations have in the past provoked violent protests across the Muslim world.
"The number of potentially inflammatory things that are said or broadcast every week (is so large) ... that warning about all of them would be useless," said Paul Pillar, former top U.S. intelligence analyst for the Middle East and South Asia. It was "impossible to predict" the kind of violent reaction that occurred in Libya, Egypt and elsewhere.
One U.S. official said, "You can't freak out on everything that's broadcast."
That official and others said the airwaves and Internet were filled with hateful material and U.S. authorities could be "crying wolf" if they issued a warning every time an anti-Islamic broadside was aired or posted online.
A senior congressional official said the question of what the United States knew about pre-Sept. 11, 2012, threats and what it did about them would likely be examined in legislative in q uiries into the Libyan and Egyptian violence.
Another aide indicated it would be difficult to fault U.S. agencies on the issue.
ATTORNEY GENERAL TO MANAGE PROBE
U.S. facilities in the Middle East were already on heightened alert earlier this week due to the anniversary of the Sept. 11, 2001, al Qaeda attacks on New York and Washington.
The FBI has opened an investigation into the killings in Benghazi. U.S. officials said Attorney General Eric Holder was cutting short a foreign trip and would return to Washington on Friday to manage the Libya investigation.
Al-Nas is an Egyptian Islamic satellite channel whose programming ranges from Islamic scholars delivering religious edicts to shows about cooking and medicine.
Before Egypt's 2011 revolution, authorities periodically suspended privately owned religious satellite channels such as al-Nas, many of which follow conservative Salafi Islam, for allegedly violating broadcasting licenses by promoting religious or sectarian hatred and providing dubious medical advice.
U.S. officials believe that al-Nas' Saturday broadcast of a talk show hosted by Sheikh Khalid Abdallah was the flashpoint for the unrest.
Egyptian political scientist Omar Ashour said Abdallah was a controversial Islamist host of a TV show that specialized in criticizing liberals, often inviting firebrand commentators to mock secular Egyptians. His show tends to be popular with Salafi Muslims, but not with followers of the more mainstream Muslim Brotherhood that dominates Egypt's government.
A European security official said intelligence reporting indicated the inflammatory clips from the American film run on the talk show had been translated and dubbed into Arabic by Copts, possibly members of the sect living in the United States.
In their commentary on the film clips, the hosts of al-Nas' program alleged the material had been uploaded by "migrant Coptics," according to Flashpoint Global Partners, a firm that monitors militant websites for government and private clients.
According to Flashpoint's translation, the al-Nas presenters at one point in their introduction to the anti-Mohammad film, specifically mentioned "radical pastor Terry Jones," the Florida preacher who staged a number of anti-Islamic events over the past year. Jones has confirmed he was involved in promoting the film.