The developments came after days of chaos that has seen numerous attacks on American and other western targets, ranging from US-branded fast food restaurants in Lebanon to a deadly assault on a consulate in Benghazi that killed the US ambassador to Libya and three others.
The protests, which appeared on Saturday to be subsiding, were galvanised by the emergence of a crude anti-Islam video called Innocence of Muslims that was made in California.
That movie, according to a lengthy trailer which has spread via YouTube, depicts the prophet Muhammad as a murderous child-molester and appears to be deliberately aimed at inflaming Muslim emotions.
Considerable mystery has surrounded the people behind the film. A film-maker from southern California called Nakoula Basseley Nakoula, 55, was interviewed by federal probation officers at a Los Angeles sheriff's station but was not arrested or detained, authorities said early Saturday.
According to the Associated Press federal authorities have identified Nakoula, a self-described Coptic Christian, as the key figure behind the movie and identified him to be "Sam Bacile", the man who claimed earlier this week to be writer and producer of the film.
Police officers said Nakoula went voluntarily with them to the police station and they were investigating to see if he had breached the term of a parole he is serving after being convicted of fraud charges.
A probation order authorized in June 2010 warned Nakoula against using false identities.
US officials, including Secretary of State Hillary Clinton, have condemned the movie's content as an attempt to denigrate an entire faith.
But the statements have done little to dampen the wave of protests and riots. Over the past few days demonstrations have been reported in Iraq, Iran, Bahrain, Afghanistan, Yemen, Egypt, Jerusalem and the West Bank, Kashmir, Malaysia, Indonesia and Nigeria.
Days of rioting across cities in North Africa and the Middle East appeared to give way to calmer scenes on Saturday.
Meanwhile in the US, the fallout from the film, and the violent unrest overseas continued.
The death of US ambassador to Libya, Chris Stevens, has shocked the American political establishment and created a serious foreign policy row in the middle of the hotly contested American presidential election.
Using hardline language, Obama promised in his weekly radio address Saturday that the attackers would be brought to justice.
"As we mourn their loss, we must also send a clear and resolute message to the world: those who attack our people will find no escape from justice. We will not waver in their pursuit. And we will never allow anyone to shake the resolve of the United States of America," Obama said.
Obama, however, also joined the chorus of condemnation of the film's content.
"I have made it clear that the United States has a profound respect for people of all faiths. We stand for religious freedom. And we reject the denigration of any religion – including Islam," he said.
The film was apparently made using actors who have said they had no idea they were making an anti-Islam film.
The offensive language about Muhammad was dubbed in later.
A 14-minute clip of the film appeared on YouTube in July but only began to generate widespread anger this week, when it was promoted by radical Islamophobic Christians in the US and then broadcast in Egypt by Islamic activists.
Nakoula appears to have a criminal record. He was arrested in June 2009, pleaded no contest to bank fraud charges a year later and was released from federal prison in June 2011 after serving a 21-month prison term, according to federal records.
In a 2010 hearing in that case prosecutors sought a longer prison term and noted that he misused some of his own relatives' identities to open 600 fraudulent credit accounts.
According to court transcripts Nakoula's defence said he only got involved in the scheme after losing his job in the gas station industry and had been forced to work for a few dollars a weekend at swap meets to try to support his children and an ailing father.
Nakoula apologized during the proceedings and his attorney James Henderson Sr said Nakoula had learned his lesson. "He's clearly gotten the message," Henderson said at the time during that court hearing. "I can't imagine him doing anything stupider than he did here."
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image: © Bengt Nyman