Authorities in Iran are to crack down on women failing to follow the regime's definition of good Islamic dress.
Iranian women currently choose to wear a range of styles
Some 200 extra police are to patrol the streets of Tehran confronting women who reveal ankles, sport thin headscarves or wear short or tight jackets.
Those found to be in breach of Iran's Islamic dress code could face instant penalty fines.
The move is part of a blitz against anti-social behaviour, also targeting drugs and people who play loud music.
People walking pets or men sporting outlandish hairstyles could also face fines, of up to $55 (£31), said Tehran's police chief, Mortaza Talai.
Iran's clerical establishment says it wants to protect the values of the country's Islamic revolution against a corrupting Western influence.
There have been many such campaigns in the past, but they have often achieved little, correspondents say.
Women's clothing has always been a political barometer in Iran, but has changed dramatically over the past decade, according to the BBC's Pam O'Toole.
During eight years of reformist rule, many young women in big cities abandoned the dark colours and long loose clothing of the early Islamic revolution for colourful headscarves and short, figure hugging coats.
That offends conservative Iranians, the grassroots supporters of the new hardline President Mahmoud Ahmadinejad, our correspondent says.
"In my opinion Islam, and the Islamic Republic, don't want to have a confrontation with people who have bad hijab," said conservative MP Fatemeh Ajorlou, who backs the campaign.
"But if someone wants to blatantly flout Islam or the Islamic system, that's another matter."
Women appear resigned to the new initiative but sceptical of its long-term effectiveness.
"Ultimately what they can do is go onto the streets and burn some clothes shops," one Iranian girl told the BBC.
"They will put pressure on us for a while. But after that it is up to people what to wear. Even if they arrest all the girls wearing bad hijab, my question is - how long can they keep them in jail?"