Mojtaba Mirtahmasb, co-director of banned Iranian filmmaker Jafar Panahi's latest film, is among six movie makers arrested by Iranian authorities, an opposition website said in a posting seen on Thursday.
Iranian media on Saturday reported the arrest of six filmmakers, but identified them only by their initials.
The others are directors Nasser Saffarian, Hadi Afariden and Shahnama Bazdar, producer Katayoun Shahabi and journalist and documentary filmmaker Mohsen Shahnazdar, said Rahesabz website which represents the opposition to President Mahmoud Ahmadinejad.
The filmmakers were arrested at their homes or offices and were transferred to the notorious Evin prison in northern Tehran, relatives said, denouncing a "new offensive" against the filmmaking community.
Mirtahmasb is the notable co-director of "This is not a Film," which he made with Panahi, who has been under house arrest in Iran.
Earlier this month Mirtahmasb was prevented from leaving the country to attend the Toronto film festival, where his documentary about Panahi was being shown, his spokeswoman said at the time.
The documentary depicts a day in the life of Panahi as he appeals his conviction for "propaganda against the system" by an Iranian court for making a film about unrest after Ahmadinejad's June 2009 disputed re-election.
Panahi was sentenced in December to six years in prison and slapped with a 20-year filmmaking ban.
Signup to our newsletter and follow us on Facebook and Twitter!
At France's Cannes Film Festival in May where his film was screened, Mirtahmasb had spoken about the tense situation for his peers.
Early this week an Iranian state television website, citing an informed source, said that six filmmakers were arrested on Saturday and identified them only by their initials.
"These identified individuals were providing the BBC Farsi with information, films, and secret reports to paint a black picture of Iran and Iranians," the website reported.
The BBC said Monday that Iran had detained six independent film makers whose work was screened by the broadcaster, but denied they were staff employees.
"The BBC is aware of reports in the Iranian media alleging that persons working for the BBC Persian service have been arrested in Iran," a BBC statement said.
Iranian authorities have banned citizens from working in any with foreign radio and television network broadcasting in Farsi, especially the BBC and the Voice of America, both popular with listeners in Iran and frequently accused by authorities of "plotting" to destabilise the Islamic regime.
"The government media are trying to put forward the version according to which Iranian filmmakers were arrested as spies in the service of the BBC," said a cinema source close to the opposition.
"This is a new offensive against the world of cinema," which for years has been the target of arrests and censorship, she said.
The Association of Iranian documentary filmmakers protested against the "irresponsible" charges against the detained filmmakers. These charges "violate their rights and add to the concerns of the world of Iranian cinema," it said on its website.
France on Wednesday called on Tehran to "free the imprisoned filmmakers" and "guarantee the full exercise of freedom of expression and creativity."