Police regularly launch campaigns cracking down on Western-style dress
Police in Iran have begun a new campaign against Western-style clothing and hairstyles.
Women are being arrested if their headscarves do not fully cover their hair or their clothes show their figures too clearly.
Men are also being stopped for having hairstyles seen as inappropriate.
BBC Tehran correspondent Jon Leyne says it is the latest such drive by the government against what is considered un-Islamic behaviour.
But he adds that many people are continuing to ignore the authorities' warnings.
The dress code imposed after Iran's 1979 Islamic revolution requires women to cover all their hair and wear long, loose-fitting clothes to disguise the shape of their bodies.
Those who violate the rules can receive lashes, fines or imprisonment.
The Iranian authorities often launch crackdowns before the hot summer months when women like to wear lighter clothing.
Squads of police have been seen in some of Tehran's major squares and parks, our correspondent says.
And in a new twist, Iranians are being asked to specify where they got the clothing or the hairstyle.
One barber's shop is already reported to have been closed down for doing hairstyles deemed inappropriate.
The Tehran police chief said it was the force's duty to prevent such things, in order to increase security and social order.
Despite the many attempts by this government to enforce Islamic standards, it seems to have absolutely no effect in north Tehran, our correspondent says, where some young women continue to perch their hejabs as far back on their hair as possible.