U.N. human rights investigators called on Iran on Thursday to end what they called a "crackdown" on women's rights activists who have been harassed and detained for seeking equal status in the Islamic Republic.
Women and men involved in a grassroots movement to collect 1 million signatures to demand full equality between women and men in Iran have been "particularly targeted", they said.
"Over the past two years, women's rights defenders have faced an increasingly difficult situation and harassment in the course of their non-violent activities," said Margaret Sekaggya and Yakin Erturk, the U.N. special rapporteurs on human rights defenders and violence against women.
"Peaceful demonstrators have been arrested, detained and persecuted with prison sentences having been imposed on many of them," the two experts said in a joint statement.
The independent investigators, who are both women, report to the U.N. Human Rights Council.
Dozens of activists were detained since the launch of a campaign in 2006 to demand changes to laws denying women equal rights in matters such as divorce and child custody. Most were freed after a few days or weeks.
Iran says it follows sharia, Islamic law, and denies accusations that it discriminates against women.
They urged Iran to comply with the International Covenant on Civil and Political Rights which guarantees fundamental freedoms including the right to opinion and peaceful association.
Iran is among 163 countries to have ratified that treaty.
An Iranian-American student, Esha Momeni, was detained on security-related charges in mid-October during a visit to Iran from the United States to see family and carry out research on the women's movement in Iran. She was freed on bail last week.
Earlier this month the Iranian Nobel Peace laureate Shrin Ebadi criticized Tehran's new Islamic penal code, saying it remains unfair to women and uses an "incorrect" interpretation of Islam.
The new Islamic penal code, whose details are yet to be debated by parliament, has been criticized for an increased imposition of harsh punishments such as flogging and execution for a variety of crimes.
Critics have also complained about the unchanged age of legal responsibility, which deems a boy punishable from the age of 15 and a girl from the age of nine.