Scuffles broke out in the Nile Delta city of Mansoura after supporters of President Mohamed Morsi marched in the city hours ahead of a speech by the president Wednesday.
The march met regime opponents, with clashes ensuing.
Hundreds exchanged rocks and Molotov cocktails, while rounds of fire resounded in the area. Hundreds of shops shut down their busines in the hostile environment, according to Al-Ahram's Arabic language news site.
Police forces used teargas in an attempt to disperse the crowds. It has not been confirmed how the clashes erupted.
Gehad Hadad, spokesman of the Muslim Brotherhood, said that one was killed and 55 injured in the melee. The Ministry of Health is yet to confirm death and injury tolls.
Morsi's speech comes days ahead of planned mass protests, mainly in Cairo, against him Friday and Sunday by opposition forces with the intention of toppling him.
His supporters are planning to hold counter rallies on both days, fuelling speculation over potential violence.