Violent clashes between police forces and civilians broke out late Sunday in front of the InterContinental Semiramis Hotel on Cairo's Nile Corniche.
Al-Ahram's Arabic-language news portal reported that a number of rioters had set a police vehicle ablaze, before Central Security Forces replied with teargas.
Tens were arrested during the melee, according to the same report, whereas the injury toll is still unknown. No deaths have been reported either.
As confrontations have been back and forth, several protesters chanted anti-interior ministry slogans and called for the ouster of President Mohamed Morsi, who has been in power for eight months.
The free-for-all came after a police crackdown on the nearby Tahrir Square.
Early on Sunday, security forces had re-opened Tahrir Square, the epicenter of the 2011 revolution, removing tents and evicting peaceful protesters.
Barbed wire across the entrances to the square from Qasr El-Nil Bridge and Abdel-Moneim Riyad Square was removed, allowing traffic to flow normally for the first time in three months.
The move to re-open the square came after skirmishes late on Saturday between security forces and unknown assailants, who had blocked the corniche in front of the Semiramis Hotel. Molotov cocktails were thrown at the security forces.
Other clashes, meanwhile, were intermittent in Port Said till the late hours of Sunday. The Canal City, among others, has been recently witnessing fierce anti-Morsi protests and calls for civil disobedience.