The political upheaval in Iran shows no sign of dying down, with the calls for new, even bigger demonstrations today. Despite the official clampdown on media reports and the internet, video smuggled out of Tehran shows protests continuing last night with police unable or unwilling to take control.The defeated Presidential candidate Mir Hossein Mousavi has proclaimed today a national day or mourning for those killed and injured in Monday’s street clashes. Evidence has also emerged of an attack on Sunday at the University of Tehran, said to have been the work of Islamic militiamen. Activists say four students died in the violence. The authorities are becoming increasingly uneasy and have accused Iran’s traditional bogeyman America of ‘intolerable interference.’ Hundreds of people are reported to have been arrested, but Iran’s Supreme Leader Ayatollah Ali Khamenei is expected to take a more conciliatory line at Friday Prayers tomorrow.