Government opponents shouted "Allahu Akbar" and "Death to the Dictator" from Tehran's rooftops in the pouring rain on the eve of student demonstrations planned for Monday. Authorities choked off Internet access and warned journalists working for foreign media to stick to their offices for the next three days.

The measures were aimed at depriving the opposition of its key means of mobilizing the masses as Iran's clerical rulers keep a tight lid on dissent. Government opponents are seeking, nonetheless, to get large numbers of demonstrators to turn out Monday and show their movement still has momentum.