Scuffles between supporters and opponents of Egypt's Islamist President Mohamed Morsi have injured up to 16 in the northern port city of Alexandria.

Organizers of an opposition movement campaigning for Morsi's ouster say their group was attacked by the president's supporters on Wednesday night.

Khaled el-Qadi and Shereef el-Gamal of the Tamarod, or Rebel, movement say the attack happened in the Abu Suleiman district and that two 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 Tamarod activists.

The scuffles came hours after Islamist parties raised tensions by calling for demonstrations on June 21 to counter massive rallies by Tamarod scheduled for the end of the month.