The Muslim Brotherhood had vowed to go ahead regardless with the weekly protests it has organised after noon prayers ever since Islamist president Mohammed Morsi was overthrown in a July 3 military coup.
Late Thursday the interior ministry warned against unauthorised protests, after police detained prominent blogger Alaa Abdel Fattah, in a stark declaration of intent reminiscent of the autocratic rule of veteran strongman Hosni Mubarak, ousted in a popular uprising nearly three years ago.
Tear gas was also fired on dozens of Islamists in Cairo's Mohandessin district and on a key road leading to the pyramids.
Protesters retaliated by throwing stones and burning tyres in Mohandessin, officials said, adding that similar protests were also dispersed in the cities of Alexandria, Suez, Mahallah and Qena.
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Egypt's army-installed government say the new law requires protest organisers to give three days' written notice to the authorities before holding any demonstration.
The interior ministry yesterday warned against "demonstrations that break the law without obtaining prior permission from security forces" and said "it will deal with these illegal activities firmly and decisively."
Interim president Adly Mansour issued the demonstration ban last Sunday and police have since enforced it, sometimes bloodily.
Yesterday, an engineering student was killed during an Islamist demonstration at Cairo university, health officials said.
To the anger of secular supporters of Morsi's overthrow, police have taken action against all demonstrations, not just those organised by the ousted president's Islamist backers.