Egyptian police have arrested nearly 200 people, clamping down harshly on Islamists defying a new law banning unauthorised demonstrations that has also angered prominent secular activists.
Despite the law decreed on Sunday, the Muslim Brotherhood vowed to go ahead with protests it has organised after weekly prayers ever since the military ousted president Mohamed Morsi on July 3.
Friday's protests come a day after police arrested prominent blogger Alaa Abdel-Fattah, in a stark declaration of intent reminiscent of the autocratic rule of president Hosni Mubarak, who was driven from office by a popular uprising nearly three years ago.
In Cairo, police used tear gas against hundreds of Morsi supporters who had gathered in front of one of the capital's presidential palaces, a reporter said, adding that he also heard gunshots.
They also fired tear gas at dozens of Islamists in the capital's Mohandessin district and on a key road leading to the Giza pyramids.
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Protesters retaliated by throwing stones and burning tyres in Mohandessin, officials said.
Other protests were dispersed in second city Alexandria, as well as in Suez, Mahallah and Qena, but details were sketchy.
At least 183 people were arrested across the country, including 106 only in Cairo, the interior ministry said, and eight people were wounded.
Friday's incidents came two days after an Alexandria court jailed 14 women to 11 years in jail and seven girls to juvenile detention for participating in a violent pro-Morsi demonstration last month.
The harsh jail terms raised calls from rights groups for a presidential pardon.
But Ali Awad, adviser to interim president Adly Mansour, said on Friday that "reports of a presidential pardon granted to these women are incorrect".
"Any presidential pardon is possible only after a final verdict" is delivered, he said in a statement on the government's official website.
Mansour issued the new protest law on Sunday, and police have since enforced it, at times bloodily.
It requires organisers to seek authorisation three days ahead of any planned demonstration, and permission can be denied if the event is deemed as a threat to Egypt's security.
To the anger of secularists who supported Morsi's overthrow, police have acted against all demonstrations, not just those organised by the ousted president's backers.
Activists say the ban is hypocritical, as the army justified the ouster as a response to mass demonstrations across the country against Morsi's turbulent single year in power.
