Police in Iran have arrested a group of mostly female actors who were making pornographic films, a crime that carries the death penalty under the country's Islamic laws, local media reported today.

The arrests were made at a house in a middle-class area in the east of Tehran, the pro-reformist website Fararu said.

The website did not specify how many actors had been detained, but said most were "beautiful young women".

Citing an "informed source" in the intelligence deputy's office of the Iranian law enforcement agency, it said the actors had produced several amateur films which had then been sold on the black market.

The directors of the films have also been arrested.

While an underground porn market has flourished in Iran in recent years, it is rare for the police to acknowledge it with high profile arrests.

Official crackdowns on "immorality" have on occasion led to raids on rave events – often denounced by the authorities as "satanist" – at which alcohol consumption and sex orgies were alleged to have occurred.

MPs attempted to combat the growth of a local porn industry in 2007 when they passed a bill approving execution for those convicted of producing obscene films.

The legislation states that "producers" and "main elements" of such works could be sentenced as "corrupters of the world", a phrase from the Qu'ran referring to those considered deserving of the death penalty for their crimes.

The law followed an outcry over the widespread distribution of an illicit DVD showing Zahra Amir Ebrahimi, a well-known Iranian soap opera star, apparently having sex with her former boyfriend.

Ebrahimi later claimed the film was a fake made by her ex-partner as an act of vengeance.

Prosecutors carried out an investigation to find its distributors after more than 100,000 copies were sold on the black market.

Dr Naser Fakouhi, one of Iran's leading sociologists and the head of anthropology at Tehran University, has warned that the country's huge number of young people – roughly 70% of the population are aged under 35 – has caused an explosion in internet pornography and the rapid growth of an underground industry.

The trend has been compounded by a rise in the average marrying age in a society in which premarital sex is outlawed and socially frowned upon.

A recent survey by the state-run national youth organisation revealed that the average marrying age had risen to 40 for men and 35 for women, well above the government's recommended guideline of 29.