Iranian officials have arrested six people accused of teaching Zumba dancing and trying to “change lifestyles”, media reports say.
The group of four men and two women were charged over their dancing and not adhering to the hijab dress code.
Instructors allegedly “attracted boys and girls, taught them Western dances”, and posted videos to social media.
The Latin American fitness routine has proved controversial in Iran, which has laws restricting dance.
“The members of a network teaching and filming Western dances have been identified and arrested,” Hamid Damghani, a commander of Iran’s Islamic Revolutionary Guard Corps, was quoted as saying by local media outlets.
“They were arrested by the Guards’ intelligence forces while teaching and creating video clips… as they sought to change lifestyles and promote a lack of hijab,” he said.
Hijab rules govern the wearing of headscarves and clothing in public places by women, and dancing with the opposite sex is banned, except in front of immediate family members.
The case has some parallels to the 2014 arrest of six Iranians for dancing along to Pharrell William’s song Happy – which saw them sentenced to 91 lashes and a prison term.
Mr Damghani said dancing as a sport “is a serious issue”.
But Zumba, the aerobics-dance hybrid popular in the West as a fitness class, has taken off in Iran despite the restrictions.
In June this year, the country’s sporting federation said the exercise included “rhythmic motions and dance and are unlawful in any shape and title”.
That was met with derision on social media, with many comparing the ban on Zumba in gyms to the hardline actions of the so-called Islamic State.
One gym manager told the Aftab-e Yazd newspaper that he would simply teach Zumba, but call it something else.
“We need to have these classes. We have been teaching Zumba for 12-13 years and if they ban it, we will continue our class under a different name,” he said.
“Zumba is one of the most profitable activities and the clubs cannot ignore Zumba.”