Iran has arrested eight people for "un-Islamic" modelling online.

The arrests are part of a wider crack down by Tehran's cybercrimes court, according to the BBC. The operation has targeted women who have posted photos of themselves online not wearing headscarves – a legal requirement in Iran since 1979.

The individuals arrested were not named but were held for working for online agencies the authorities deemed to be un-Islamic, according to a prosecutor. The eight arrested were among 170 investigated for being involved in modelling. They included 51 salon managers and designers, 58 models and 59 photographers and make-up artists, according to a court statement.

Javad Babaei, the court's prosecutor, made the announcement in a state television broadcast on Sunday night that discussed the "threats to morality and the foundation of family" posed by social media.

Babaei said the agencies had been "making and spreading immoral and un-Islamic culture and promiscuity".

He went on to say that 29 people had been threatened with a criminal investigation but those who "reformed their behavior" did not face court action. "Eight out of the 29 have been arrested," he confirmed.

A spokesman for the Iranian Centre for Surveying and Combating Organised Cyber Crimes, Mostafa Alizadeh, said: "Sterilising popular cyberspaces is on our agenda.

"We carried out this plan in 2013 with Facebook, and now Instagram is the focus." He added that more crackdowns would begin in the coming days.