Two members of the alumni association of the country's largest reformist student group have been detained by security forces in Tehran, a member of the association has told RFE/RL's Radio Farda.
Amir Rashidi said Hassan Assadi-Zeidabadi, who heads the Human Rights Committee of the Office to Foster Unity, and Ali Jamali, a member of its Central Council, were taken into custody on August 22.
He said it was not clear why they were detained and where they were being held.
Assadi-Zeidabadi was previously arrested in November 2009 on charges of "assembly and conspiracy against the regime," "spreading propaganda against the regime," "disrupting public order," and "insulting Iran's president."
Assadi-Zeidabadi was released on bail after 40 days in prison. His trial began a few weeks ago, but the verdict has not yet been pronounced.
A number of the group's members have been arrested since the disputed presidential election in June 2009. Rashidi described the two recent detentions as the start of "a new wave of pressure against the Alumni Association of Iran."
Prominent journalist and association head Ahmad Zeidabadi has been imprisoned since June 21, 2009. He was sentenced to six years in jail, five years of internal exile in the city of Gonabad, and a lifetime ban on all social and political activities.
Zeidabadi was awarded the Golden Pen of Freedom award for 2010 by the World Association of Newspapers and News Publishers.
Association spokesman Abdollah Momeni was arrested on June 21, 2009. He was sentenced to four years and 11 months in prison.
Momeni, together with student activist Majid Tavakoli, was the recipient of the Homo Homini prize bestowed by the Prague-based NGO People in Need.