The physical condition of a supporter of the Mourning Mothers of Iran women's group is reported to have worsened during the month since her arrest, RFE/RL's Radio Farda reports.
The Mourning Mothers of Iran unites women whose children were killed or imprisoned during the crackdown that followed the disputed June 2009 presidential election that returned Mahmud Ahmadinejad to power.
Its members have been repeatedly harassed by the government.
Hakimeh Shokri, 38, was arrested on December 5 while attending a gathering of the Mourning Mothers in Tehran.
The group had gathered at Behesht Zahra Cemetery to mark the birthday of Amir Arshad Tajmir, who was killed during the Ashura day protests in December 2009.
Shokri's brother Iraj Shokri told RFE/RL on January 9 that he was recently permitted to visit her for the first time since her arrest.
"Hakimeh told me that she fell ill under interrogation and had to be taken to the hospital," Iraj Shokri said.
Shokri added that his sister was an ordinary citizen, not a political activist: Hakimeh went to the cemetery that day merely to sympathize with families who had lost their loved ones, he said.
Hakimeh Shokri is currently being held in Evin prison on charges of espionage and "acting against national security."Read more in Persian here