Demonstrations erupted in Cairo's Tahrir square Monday night, while in the nearby neihborhood of Dokki, presidential candidate Ahmed Shafiq's campaign headquarters was set ablaze.
Protestors in the square are unhappy at Egypt's election results that have pitted the Muslim Brotherhood's Mohamed Morsi against former Prime Minister Ahmed Shafiq - both candidates disappoint activists.
Ahram Online reported that during Monday's demonstrations clashes broke out between "thugs" - often government loyalists who many believe are paid to attack protestors - and those demonstrating.
Read more on GlobalPost: Egypt goes to the polls, Muslim Brotherhood triumphant
Reuters reported that rocks flew as demonstrators battled stick-carrying thugs.
Demonstrations also occured in Alexandria.
Earlier in the evening, presidential hopeful Ahmed Shafiq's headquarters was broken into and torched by unknown assailants, AFP reported.
Arrests were said to have been made.
There were no reports of injuries and the fire was quickly put out.
The run-off election between Morsi and Shafiq is set for June 16 and 17.