Iranian women given special permission to attend a football match (AFP)

UPDATE, 0730 GMT:

Four of the six detained women were released on Saturday, after the publication of Human Rights Watch’s appeal.

Human Rights Watch has called on Iran’s authorities to release women who have been detained for going to a football stadium.

Six women have been held since Monday for defying a ban enforcing men-only crowds. They include Zahra Khoshnavaz, a prominent advocate for ending the ban, and Forough Alaei, an award-winning photojournalist who has documented the defiance of women dressing as men to get into the stadium.

The women are in Qarchak Prison, south of Tehran, which has been condemned by activists over its poor hygiene.

Iranian authorities have defended the ban by saying women must not be exposed to the swearing of male spectators.

Football’s world governing body FIFA is threatening sanctions, including a bar on Iran’s involvement in tournaments, if steps are not taken for the admission of women.

FIFA has set a deadline of October 10, the date of Iran’s first home World Cup qualifier against Cambodia.

The ban has been lifted occasionally for select groups of women, and President Hassan Rohani has called for a permanent removal. But hardliners, including Iran’s judiciary, have insisted that the restriction must remain.