A viral video of male and female teenagers at a skateboarding day in the southern city of Shiraz has angered Iranian officials, who have arrested 10 participants for their role in the event.
The video, which was posted on social media on June 23, shows several teenagers of both sexes mixing freely on a boulevard in Shiraz to mark "Go Skateboarding Day."
The hijab became compulsory in Iran in public for females over the age of 9 following the 1979 Islamic Revolution.
Many Iranian women have flouted the rule over the years and pushed the boundaries of what officials say is acceptable clothing.
Many have publicly criticized the restrictions and a large number of the females in the video were not wearing headscarves.
The Mehr news agency reported, quoting Shiraz Governor Lotfollah Sheibani, that "so far 10 people who organized the event have been arrested."
"The main organizer of the event has also been identified and action has been taken to arrest him based on judicial authorities," Sheibani said.
"The actions of the teenagers in this gathering are a violation of religious norms, and we strongly condemn these actions and deal with them judicially" he added.
In recent years, Iranian adolescents have repeatedly challenged the regime's efforts to control various aspects of social life.
Iranian media reported last weekend that police had arrested 120 people for alleged "criminal acts," including drinking alcohol, mixed-sex dancing, and not wearing a hijab at a party in a forest in the country's north.