Thousands of Iranian women have come together in an online campaign for greater social freedoms, posting pictures of themselves flouting the Islamic dress code required of all women in public.
More than 146,000 people have supported the Facebook page "Stealthy Freedoms of Women in Iran," which was created just 10 days ago with the aim of sparking debate on whether women should have the right to choose to wear the hijab.
It has yet to provoke an official response from the Iranian authorities, who fear people are letting Islamic values slip as they turn towards a more Western lifestyle.
The hijab, which is obligatory in Iran, requires women to cover their hair and much of their body in loose clothing in public. It has become a defining feature of Iran's interpretation of sharia, or Islamic law, since the 1979 revolution.
More than one hundred photos have already been posted on the page, with young women posing bare-headed in the countryside, suburbs, by the sea and even in cities.
"This is me committing a crime," wrote a girl who posted an image of herself sitting in the middle of a secluded road in Nour Forest in northern Iran, with her headscarf resting on her shoulder. "Covertly, but in absolute peace," her caption said.
Another photo shows a grandmother, a mother and her daughter together on a pavement.
"In one frame, three generations secure freedom at a corner of this street," read the caption.
"Here's hoping the day comes when the next generation can exercise its most basic right, before their hair goes grey."
For more than a decade, the issue of the hijab has been hotly contested between hardline authorities and ordinary women pushing its boundaries.
A dedicated morality police has long handed out fines, verbal notices or even arrests to women it considers are not observing the hijab rules properly.
The unit has reportedly been ordered to exercise more restraint since President Hassan Rouhani, a self-declared moderate, took office in August promising greater social freedoms.
But regime hardliners are opposed to any relaxing of the rules.
Last week, thousands of religious conservatives held an unauthorised protest in Tehran, urging the government to confront what they say is the increasing flouting of the Islamic dress code