The trial opened on Wednesday of an Egyptian Copt accused of blasphemy after posting on the Internet an anti-Islam video that sparked violent protests worldwide, an AFP reporter said.

Albert Saber, 27, was arrested at his home in Cairo on September 13 after neighbours alerted authorities that he had posted clips from "Innocence of Muslims" on social networking sites.

The low-budget film made in the United States caused outrage for mocking Islam and portraying the Prophet Mohammed as violent and immoral.

Saber faces up to five years behind bars in a case that has sparked condemnation from human rights groups and raised concerns over freedom of expression under Islamist President Mohamed Morsi, the first president after an uprising that toppled Hosni Mubarak.

"Albert has nothing to do with the offensive film but the case was a way to calm down popular anger," Saber's lawyer Ahmed Ezzat, a Muslim, told AFP outside the court.

The trial "comes in a general atmosphere of discrimination and bad management of justice especially when it comes to minorities," Ezzat said.

Authorities had broken into Saber's home while he was in detention.

His mother, Kariman Masih said she was "shocked, terrified" by what is happening.

"I can't believe all that is happening to us and to my son," she told AFP.

"I'm defending my son and his right to expression. Didn't the revolution call for freedom?," she said.

Ezzat said Saber had launched discussions about religion online and "criticised fundamentalist men of religion."

"The problem is with the articles in the law and not what Albert did. The law relating to blasphemy can be interpreted in 100 different ways," Ezzat added.

Copts have repeatedly criticised authorities for what they say are double standards when it comes to cases of blasphemy and offence to religion.

Egypt's Christians, who make up six to 10 percent of the 82 million population, have regularly complained of discrimination and marginalisation. They have also been the target of numerous sectarian attacks.

Ahmed Seif al-Islam, a lawyer and member of the National Council for Human Rights who attended the hearing, said the case "is linked to the charged atmosphere caused by the film."

"We are here to support a fair trial, fairness has nothing to do with religion," said Seif al-Islam.

Saber's case is likely to fuel the fears of Egypt's Copts who fear that the anti-Islam film will lead to further persecution at home, particularly as "Innocence of Muslims" was apparently produced by a Coptic Christian film-maker in the United States.