Clashes broke out between police and groups protesting the election results from early morning on Saturday onward. Initially, the protests were largely peaceful. However, as time passed, they became increasingly violent. In a stand-off that later took place in north Tehran between supporters of Ahmadinejad and Mousavi, an angry throng of people broke into shops, started fires, and tore down signs. Civil unrest took place as riot police on motorbikes used batons to disperse Mousavi supporters who staged a sit-in near the interior ministry, where the results were announced. Up to 2,000 Mousavi supporters erected barricades of burning tyres and chanted "Mousavi take back our vote!".