Iranian police have arrested more than 260 people, including three European citizens, on suspicion of spreading satanism, the state-run IRNA news agency reported Friday.

The report said the suspects were arrested on Thursday night in Shahryar County, west of the capital of Tehran, for “spreading the culture of satanism and nudity.” It did not elaborate.

It was not clear how such a large number of arrests were made in one night — if the suspects were in one location, at some gathering or party, or not.

Gatherings where unrelated men and women are seen together are illegal in Iran and considered a sin under Islamic law.