With the foreign media banned, the internet restricted, and the mobile phone network shut down, the Iranian authorities are doing their best to suppress any news about the latest anti-government protests.
Pictures that did get through via the internet appear to show thousands marching peacefully in Tehran and four other cities, Isfahan, Shiraz, Tabriz and Kermanshah, when they were tear-gassed and baton-charged. Dozens have reportedly been arrested.
Defying a ban, the crowds began marching in silence, to express their solidarity with the people of Tunisia and Egypt and, by association, identify with their plight.
News agency reports say things got uglier as the security forces moved in, some using Tasers and paintball guns. Several dustbins were set on fire, and the chanting began.
“Death to the dictator” could be heard in several places, a reference to Supreme Leader Ayatollah Ali Khamenei.
While the security forces had initially shown restraint, the situation degraded further as the day wore on, and squadrons of motorcycle-mounted Islamic militia could be seen riding around looking for demonstrators.
Here is a selection of amateur footage: