Iranian security forces have arrested more than 260 people, including three European nationals, at a "Satanist" gathering west of the capital Tehran, the semi-official new agency Tasnim reported on Friday.
The raid follows a nationwide crackdown against women accused of flouting Iran's strict Islamic dress code.
"Satanist network broken up in Tehran, arrests of three European nationals," Tasnim wrote.
It said 146 men and 115 women had been arrested and that alcohol, banned under Iran's Islamic laws, and psychedelic drugs had been seized.
The news agency also published photographs alongside its report showing masks, what appeared to be model skulls and T-shirts with skulls on.
Information on the other nationals arrested
The report did not give the nationality of the Europeans.