The arrest appears to be the latest jailing in an official clampdown to silence dissent and depict government critics as threats to the public.
Maryam Hosseikhah, a member of the One Million Signatures Campaign Against Discriminatory Laws, was detained on November 18 and transferred to Tehran's Evin prison.
Authorities had told her one day earlier that she was being charged with "acting against Iran's national security" and publishing false information on the Women's Cultural Center and the One Million Signatures Campaign websites.
Hosseikhah's husband, Shahab Mirzayi, told Radio Farda on November 18 that his wife was active in efforts to combat gender-based discrimination:
"Maryam and some of her friends were writing on these websites," Mirzayi said. "The issues are not political, they're social issues -- they're engaged in bringing equality for men and women. They want to take a draft law to the parliament. What they're doing is legal and transparent. Unfortunately they're facing these actions -- it's not clear why they're being treated like this."
Authorities Upping Pressure
Pressure has increased recently on women's rights activists and members of the One Million Signatures Campaign.
At least two other members of the campaign have been jailed in recent months. Ronak Safarzadeh and Hana Abdi were arrested in September and October in Kurdistan Province. They remain in prison, reportedly with no access to family members or lawyers.
Earlier this month, Iran's judiciary temporarily suspended prison sentences against a women's rights activist and social worker who were arrested at a demonstration in mid-2006.
The activist, 24-year-old Delaram Ali, is among dozens of people arrested in June 2006 for protesting articles in Iranian law seen as discriminatory against women. Ali was initially sentenced to more than two years in prison and 10 lashes.
At least five other female activists who organized the Tehran protest were given suspended jail terms earlier this year.
Human rights groups have called on Iran to end official pressure on women's rights advocates and the country's civil society.