Organizers of an opposition movement campaigning for Morsi's ouster say the scuffles broke out in the Abu Suleiman District on Wednesday night when two opponent activists and four residents were hurt.
An official from Morsi's Muslim Brotherhood, Anas al-Qadi, gave a different account. He says six Brotherhood members and four storekeepers were injured in an attack by opponent activists.
The scuffles came hours after Islamist parties raised tensions by calling for demonstrations on June 21 to counter massive rallies by opposition scheduled for the end of the month.