Police dispersed the crowds, beating up both male and female protesters. But by nightfall there were still sporadic disturbances across the capital, with palls of smoke rising across the skyline from burning tyres. As darkness fell, victorious Ahmadinejad supporters cruised the streets on motorbikes, shouting victory. Onlookers said they had not seen such disturbances since Iran's student-led uprisings in 1999, and their scale showed the potential for the showdown to spill over into further challenges to the Islamic establishment.