Clashes broke out between supporters and opponents of the Muslim Brotherhood in the large Delta town of Tanta, Ghariba governorate, in the late hours of Sunday as violence over president Mohamed Morsi’s decree escalated.

According to Ahram’s Arabic-language news website, anti-Brotherhood protesters have hurled Molotov cocktails at the headquarters of the Islamist group’s Freedom and Justice Party (FJP).

Both sides then engaged in a fistfight that has reportedly left 15 protesters injured.

A 15-year-old Brotherhood member was killed in the Nile Delta city of Damanhour earlier in the day in similar clashes.

A controversial decree issued by Morsi on Thursday, which shields his decisions from legal challenges and protects the upper house of parliament and the constituent assembly from dissolution, sparked violence in a number of cities, including Cairo, Alexandria, Port Said and Suez.