TEHRAN– An Iranian website said Thursday that authorities briefly arrested and then released the granddaughter of the architect of the Islamic revolution, Ayatollah Ruhollah Khomeini, and her husband. The report by the pro-reform Rahesabz Web site couldn't be independently confirmed, but the site has been credible in the past. It says Zahra Eshraghi and her husband Mohammad Reza Khatami, the brother of a former presient, were in custody Thursday for an hour. It would rank among the most high-profile detentions by authorities, who have waged a massive crackdown before events Thursday marking the 1979 Islamic Revolution, which was led by Eshraghi's grandfather. Low-level clashes are reported around Tehran, including an attack on the car of opposition leader Mahdi Karroubi.