To celebrate the Persian New Year, President Obama sent a videotaped message to the people of Iran. But his references to a "new day" for relations between Washington and Tehran may not be heard by many women there.

Roxana Saberi, a 31-year-old Iranian American freelance journalist from Fargo, N.D., has been in the infamous Evin prison for more than a month. The regime announced two weeks ago that it had completed its investigation of Saberi and reportedly planned to release her in "a few days." Saberi's arrest and delayed release are the latest twists in a frightening pattern of harassment and detainment of women and dual nationals by Iran's Intelligence Ministry, whose clout and reach have expanded under President Mahmoud Ahmadinejad. The ministry is behind a stepped-up campaign to silence female writers, journalists and peaceful activists.

Saberi, who has reported for the BBC, NPR and other news outlets, has lived in Iran for the past six years. Her father says that she was pursuing a master's degree and researching a book about the country's people and culture when she was arrested Jan. 31. Officials allege that Saberi was working "illegally" because her press credentials had been revoked (though the government had not previously objected to her stories).

Charges were filed in the case of Esha Momeni, a graduate student at California State University at Northridge who was arrested last October while visiting family and researching her master's thesis project. Her parents' apartment was searched, and her computer and videotapes of interviews on the Iranian women's movement were seized. Momeni, who spent three weeks in solitary confinement in Evin, was charged with "acting against national security" and "propaganda against the state."

These days, the Intelligence Ministry arrests and incarcerates people at will. Officials consider any Iranian with ties to the West a security threat and label innocent scholarly or journalistic activity as "propaganda against the system" or "acting against state security."

The targeting of dual nationals seems to have intensified as hard-liners seek to sabotage any initiative for an Iranian-American dialogue by the Obama administration. But dual nationals are not the only women being persecuted. In January 2008, the government shut down the influential women's magazine Zanan. In December, authorities raided and shut down the office of Shirin Ebadi, the Nobel Prize winner and human rights defender. Attorney Nasrin Sotoudeh, an advocate for women and children, was prevented from going to Italy to receive a human rights award for her work. Also last year, Parvin Ardalan, an activist for the women's Change for Equality campaign, was forced off a flight to Sweden where she was to collect the Olof Palme Award for human rights.

Much of the crackdown has focused on Change for Equality, a peaceful campaign that seeks to collect 1 million signatures to reform discriminatory laws against women in child custody, divorce, inheritance, equal pay and other areas. The group's Web site has been shut down more than a dozen times. Members have been arrested and beaten during peaceful protests.

The reasons for this crackdown are clear. Change for Equality, which is not connected to any sanctioned political groups or parties, is about women taking matters into their own hands. Just as authorities are trying to intimidate individual journalists and researchers, they are trying to suppress a movement over which they have no control.

Women have been at the forefront of the struggle for freedom and rights in Iran. In the environment of threat and intimidation they are enduring, they need and deserve all the international support that can be mobilized for them.

Haleh Bakhash is a Washington lawyer. She wrote this commentary for The Washington Post.