Huge crowds of protesters have been marching through Iran's capital and other cities, videos show, in what is said to be the largest show of force by opponents of the clerical establishment in years, BBC reported.
The peaceful demonstrations in Tehran and the second city of Mashhad on Thursday evening, which were not dispersed by security forces, can be seen in footage verified by BBC Persian.
Later, a monitoring group reported a nationwide internet blackout, according to BBC.
