Police in Iran have arrested 40 suspects after the devastating twin bombings of a mosque in the south-eastern city of Zahedan, according to an Iranian news agency.

Police beat protesters and fired tear gas and water cannons at thousands who rallied in Tehran today in open defiance of Iran’s clerical government, sharply escalating the most serious internal conflict since the 1979 Islamic Revolution.

Iran’s hardline president shrugged off post-election violence as “passions after a soccer match” and drew his own huge rally of support as protesters battled police and shouted their opposition from the rooftops.