Angry Egyptians standing on piles of debris and shattered glass pointed the finger of blame at the Muslim Brotherhood after a car bomb ripped through Mansoura's police headquarters on Tuesday.
"The people want the execution of the Muslim Brotherhood," shouted the residents amid the wreckage of burnt-out cars and collapsed walls left by the pre-dawn blast, which peeled off a section of the building.
Fourteen people, most of them policemen, died in the attack and more than 100 were wounded.
The cause of the explosion at a police headquarters was not immediately clear but some alleged it was a car bomb targeting security forces.
The blast shattered nearby windows and was felt over 10 miles away.
Nobody claimed responsibility for the bombing but the government pointed its finger at the Muslim Brotherhood, which it refers to as a terrorist group.
Attacks on security forces have increased since the ouster of Islamist President Mohammed Morsi by the army in July.
Agence France-Presse contributed to this report.