Authorities in Tehran have released four Iranian women from a detention center after they were arrested for allegedly dressing as men to circumvent a ban against women attending soccer matches in the Islamic republic, a Human Rights Watch researcher (HRW) says.

The researcher, Tara Sepehrui Far, said on Twitter on August 17 that the four women were freed on bail after reportedly being charged with 'trying to enter stadiums illegally.'

The U.S.-based nongovernmental rights group has highlighted the case and called on Iranian authorities to release women from Qarchak prison, south of Tehran, a facility where activists have reported poor hygiene and safety conditions.

Minky Worden, director of global initiatives at Human Rights Watch, said on August 16 that FIFA, the world governing body of soccer, should impose sanctions against Iran in order to enforce its own regulations against gender discrimination.

Far said those released on August 17 included Zahra Khoshnavaz, a prominent advocate for ending Iran's ban against women attending public sporting events.

/**/ /**/ /**/ SEE ALSO: A Score For Equality? FIFA Demands Iran Allow Women Into Soccer Stadiums

They also included Forough Alaei, an award-winning photographer who documented the women's defiance of the ban as they attempted to enter Tehran's Azadi Stadium in disguises, Far said.

Also released on bail on August 17 were Leili Maleki and Hedieh Marvasti, Far tweeted.

Reports say a total of six women have been detained since August 12 for defying the ban. The fates of the other two women were not immediately clear.

"Iranian women should not be spending a second in prison because authorities accuse them of peacefully attempting to defy a ridiculous ban that denies women and girls equal rights to attend a football match," Worden said.

She also said Iran should 'lift the discriminatory ban,' which she described as an example of 'blatant, long-standing gender discrimination."

The arrests came after a June 18 warning letter by FIFA President Gianni Infantino to Mehdi Taj, the president of Iran's soccer federation (FFIRI), that Iran must take concrete steps to allow women in stadiums or face sanctions.

In that letter, Infantino initially set a July 15 deadline for Tehran to inform FIFA of 'concrete steps' the Iranian federation would take to ensure that 'all Iranian and foreign women who wish to do so' could attend World Cup qualification games that start in September.

Infantino did not say what will happen if Tehran refuses to lift the ban on women. But activists and sports commentators have suggested that Iran's national team -- one of the top squads in Asia -- could face punitive measures, including losing points in its bid to qualify for the 2022 World Cup or even be excluded from that prestigious competition.

The head of the Professional Football Licensing Appeals Committee of Iran's soccer federation, Dariush Mostafavi, said on August 4 that FIFA set an August 30 deadline for Tehran 'to sort out the presence of women in stadiums.'

'It's not a joke,' Mostafavi was quoted by Iranian media as saying.

Copyright (c) 2018. RFE/RL, Inc. Republished with the permission of Radio Free Europe/Radio Liberty, 1201 Connecticut Ave NW, Ste 400, Washington DC 20036