CAIRO: Clashes erupted on Wednesday between supporters and opponents of Egypt's Islamist President Mohamed Morsi in the Nile Delta city of Mansura, security officials and the Muslim Brotherhood said.

Islamists had been holding a pro-Morsi rally in Mansura when opponents began throwing rubbish at them, a security official said.

"This led to clashes involving birdshot which left seven people injured," the official said. A spokesman for the Muslim Brotherhood, Gehad al-Haddad, said one person was killed in the clashes.

"55 injured & one confirmed death in attack on Pro-Morsi rally in #Mansoura," Haddad said on Twitter.

The death could not immediately be confirmed by the health ministry or security officials.

The clashes come amid widespread tension ahead of mass anti-Morsi rallies planned on Sunday while Islamist parties have called for their own rallies to support the president on Friday, raising fears of more unrest.

A campaign dubbed Tamarod (rebellion in Arabic) has collected more than 15 million signatures in support of a snap presidential election just a year after Morsi took power.