Dozens of young Iranians have been detained for "unlawful actions" after using a website to arrange dates, officials say.
Few Iranians can go online
A militia commander said 68 men and women were arrested in the capital Tehran, according to a report by Iran's official Islamic Republic News Agency (Irna).
The Basij militia also detained the operators of the dating website, Irna said.
Correspondents say the Basij enforce Iran's strict morality laws and often raid mixed parties and gatherings, but this is the first time an operation against internet users has been reported.
General Ahmad Rouzbehani told Irna: "Some people were using an internet site to allow girls and boys to talk and arrange meetings in a place in north Tehran where they had illegal relations."
He said the young people may have been duped and added that the "matchmakers" were also arrested and handed to judiciary officials.
Computers, satellite dishes and CDs were also seized in a series of raids prompted by tip-offs to the morality police, General Rouzbehani told the news agency.
He asked families to be "more sensitive to the use of the internet by their children and to prevent from their deviation by advising them, given the expansion of the [internet] facilities in the society".
Official figure show about 3% of Tehran residents have access to the internet.
Most people use net cafes to go online as there are only a handful of internet service providers in the country.
Internet chat rooms provide a way for youngsters to talk freely about taboo subjects such as sex.
Over the past year, there has been a big rise in the number of Persian weblogs, online journals where cyber-diarists let the world in on their lives.
There are more than 1,200 Persian blogs, which focus largely on social rather than political issues, such as the opposite sex, music and films.