The inflammatory anti-Islam film that has triggered rioting across the Muslim world was produced by a US religious group called Media for Christ and reportedly directed by a pornographer.

The man apparently behind the film - entitled Innocence of Muslims on its 14-minute YouTube trailer - is a US-based Egyptian Copt and fraudster who may have violated his parole, US officials said on Friday.

The film was directed by 65-year-old Alan Roberts, a veteran whose prior oeuvre was dominated by schlock soft porn and hammy action with titles like Young Lady Chatterley II and Karate Cop, according to website Gawker.

Gawker interviewed members of the cast of Innocence of Muslims, who say they were duped into appearing in what they thought was a fictional epic, only to discover their lines had been dubbed over with anti-Muslim propaganda.

Roberts's casting call lists the leading roles as George, Condalisa and Hillary, but in the finished version, the script was doctored to make them represent the Prophet Mohammed and figures from the Koran.

The film was promoted by a network of right-wing Coptic and Evangelical Christians with a radical anti-Muslim agenda, like Egyptian American provocateur Morris Sadek and Terry Jones, a Florida pastor notorious for publicly burning a Koran.

And, acting as 'consultant', was Steve Klein, a Vietnam veteran and founder of Courageous Christians United who is notorious for protests outside mosques and Mormon temples and who told AFP he helped the moviemakers.

The film itself does not appear to have broken any US laws, but Nakoula Bassily Nakoula, the 55-year-old Egyptian Copt believed to have written the film, may have breached the rules governing his conditional release from prison.

"The matter is under review," said a spokesman for the Administrative Office of the US Courts.

Early on Saturday, Nakoula was taken for questioning to a police station, local television reported.

The local NBC News affiliate said Nakoula was escorted by sheriff's deputies from his Cerritos, California, home shortly after midnight for an interview by federal probation officers.

A 2009 indictment from a US District Court in California shows that Nakoula was charged with defrauding US banks by opening false accounts and passing bad checks.

He has since been released on probation, and the document says he agreed to testify against the alleged ringleader in the check scam, but if Nakoula is now found to have broken the terms of his parole, he could go back to jail.

As part of his release terms, he was forbidden from using computers or the Internet for five years and fined $790,000.

This week saw Nakoula move from anonymous petty criminal to become a central figure in an international incident that has triggered mass protests in Muslim-majority countries in North Africa, the Middle East, Asia and Africa, and seen several US diplomatic missions attacked.

Reporters and police are camped out outside Nakoula's house in Cerrito outside Los Angeles, but he has not been seen, although he did give an interview to Radio Sawa, a US-government station that broadcasts in Arabic.

'Nobody manipulated my film'

"I am the one who leaked the 14 minutes and put it on the Internet and I am thinking about releasing the full film. Nobody manipulated my film," he said. The clip on YouTube was picked up by Egyptian television.

The film has amateurish production values, with actors in laughable false beards appearing to hover weightlessly in front of stock desert footage.

But its depiction of the Prophet Mohammed as a thuggish deviant offended many Muslims, and sparked a wave of anti-American protests that have cost several lives and seen mobs burn US missions, schools and businesses.

According to Paul Audley, president of Film LA, which issues filming permits in Los Angeles, a group called Media for Christ was issued a one-day shooting license in August 2011 for a film with the working title "Desert Warriors."

"I do know personally for having looked at it, before it was withdrawn, that the producer's name on it is Sam Bossil," he said in an interview. Bossil is believed to be one of the pseudonyms used by Nakoula, who uploaded the clip as "Sam Bacile."

A man identifying himself as Sam Bacile gave interviews to US media this week in which he claimed to be an Israeli-American Jew who made the film to help Israel, but a consultant on the movie has since debunked this claim.

Media for Christ's websites and Facebook page were taken down without explanation Friday, but the group is reportedly a right-wing conservative operation founded by Joseph Nasralla Abdelmasih, an Egyptian Copt.

"Media For Christ is a place to discover the word of God and the Gospel preached by many different ministries and ministers in the Lord," the brief introduction to the otherwise defunct website reads.

The group is based just outside Los Angeles in the city of Duarte, where city manager Karen Herrera confirmed it holds an active business permit.