Dozens were wounded late Tuesday as supporters and opponents of deposed president Mohamed Morsy clashed at Daqahlia's Mit Ghamr, another episode in the lates spate of violence following the removal of the president by the armed forces two weeks ago.
Clashes on Saad Zaghloul Street spread to the Muslim Brotherhood's local administrative office as anti-Morsy protesters hurled Molotov cocktails at the building.
The office soon caught fire.
A group of Morsy supporters managed to defend the Freedom and Justice Party office from further attack.
Egyptian authorities had earlier summoned several Islamist politicians for questioning, including the Brotherhood's Supreme Guide Mohamed Badie, over accusations they incited supporters to attack their opponents as well as members of the security forces.
The last spate of violence left seven dead in separate clashes in Cairo and Giza late Monday.
Edited translation from Al-Masry Al-Youm