Iran's powerful Islamic Revolutionary Guards Corps (IRGC) said it has summoned, detained, and warned some 450 administrators of social-media groups in recent weeks.
The announcement on August 23 was carried on a website affiliated with the IRGC's cyber arm, Gherdab, and said the unspecified number of detained people used social media like the messaging app Telegram, which is popular in Iran.
The announcement said those detained or summoned made posts that were considered "immoral." It said, without elaborating, that the IRGC only took action after "judicial procedures" were completed, and some people will face trial.
"These people were carrying out immoral activities, insulted religious beliefs, or had illegal activities in the field of fashion," said Gherdab.
In May, authorities announced an operation targeting modeling posts on Instagram. Several people were arrested for posting pictures of women without head coverings -- a crime in Iran.
The arrests are part of a larger cultural struggle in Iran between hard-liners and moderates over the country's future.
Despite restrictions, more than half of Iran's population of 80 million is online. Telegram alone has more than 20 million users.
Based on reporting by AP, AFP, and dpa