Friday's violence between supporters of ousted President Mohamed Morsi and either security forces or other supporters of the crackdown appeared more widespread than on either of the last two protest days.
A witness saw three men with swords set upon one of thousands of pro-Morsi protesters marching through Egypt's second city, Alexandria. Medical sources said one person involved in that protest was killed.
Another Morsi supporter was seen with birdshot wounds to the face, and Brotherhood supporters were seen punching and kicking a man they presumed to be hostile to them, the witness said.
State television showed footage of soldiers armed with assault rifles searching buildings in Alexandria, saying they were looking for gunmen who had opened fire on them.
One Morsi supporter was killed in Kafr el-Bateekh in Damietta province in clashes with government supporters where rocks, sticks and birdshot were used, according to witnesses and a medical official.
The authorities, however, pressed on with a campaign to neutralize Egypt's biggest political movement with a decision to clip its legal status.
Far from returning to normality after the army's overthrow of Morsi on July 3 following mass protests, the Arab world's most populous nation has remained on edge in fear of violence.
That fear was reinforced on Thursday when Interior Minister Mohamed Ibrahim survived a presumed suicide car bomb targeting his convoy, the culmination of a series of militant attacks.
Although it has yet to assign blame for that attack, the interim government has accused Brotherhood leaders of inciting violence, and portrayed the crackdown on the movement as a fight against terrorism - a view that many Egyptians endorse.
The new establishment has unveiled plans to revise the constitution to remove some amendments pushed through by Morsi, as well as lifting a ban on Mubarak-era officials returning to public office, before holding parliamentary and presidential elections early next year.
NTJ/SHI