Iranian media say authorities have arrested six young people for promoting Zumba, the Latin-inspired dance exercises, and other types of exercise.
The arrests are part of Iran's decades-long crackdown against influences of Western culture. In June, Iran banned Zumba and other exercises considered un-Islamic.
Thursday's report says the six included two women. They were arrested by the powerful Revolutionary Guard in the town of Shahroud, about 400 kilometers, or 250 miles, east of the capital, Tehran.
Such arrests and raids are common in Iran.
The report also says the suspects published videos of Zumba moves and exercises on social networks - and encouraged young women to take off their Islamic head-covering in public places.
Under the law, women in Iran should cover their hair and avoid figure-hugging attire.