Farhad Poulaid, an Iranian working for the French wire service AFP, was detained as he rode through central Tehran on a motorbike and nothing has been heard from him since. Nafiseh Zareh Kohan, an Iranian who writes for reformist publications, and Niels Krosgaard, 31, a Danish journalism student, were also held, the International Federation of Journalists said yesterday.

The arrests are part of a sustained crackdown on all independent media, foreign and domestic, in the five months since President Ahmadinejad’s hotly disputed re-election triggered the most serious unrest in the Islamic Republic’s 30-year history.