Fifteen student activists and the mother of one of them were arrested today in Tehran on the eighth anniversary of a bloody attack by police officers and vigilantes on a university dormitory in the Iranian capital. According to the Associated Press, six students were attacked, beaten up, and detained by the police and plainclothes security agents as they staged a sit-in at the main entrance to Amir Kabir University, a leading technology institution. They were protesting the imprisonment since May of eight student leaders from the university, including three editors of student newspapers.

Nine other students and the mother were attacked and detained later today after government agents broke windows and forced their way into the downtown offices of the leading pro-democracy student organization, the Office for Fostering Unity. Today’s arrests were the latest in a simmering confrontation between pro-reform students and the government of Iran’s hardline president, Mahmud Ahmadinejad.

The arrests were part of a repression of dissent that was ushered in by the election of Mr. Ahmadinejad, in 2005, and that intensified more recently with the arrest of other student leaders and the imprisonment of prominent Iranian-American scholars on spying charges. —Burton Bollag