Muslim Brotherhood supporters have marched in solidarity with Gaza, which has been under attack from Israel for 11 days.
The National Alliance to Support Legitimacy (NASL), a pro-Mohamed Morsi coalition, called for protests in Cairo and Giza against the "American-Zionist conspiracy," Al-Ahram Arabic news website reported.
Marches started in Cairo's Zeitoun district, and police dispersed a march in Al-Mounib after protesters blocked traffic.
In Giza governorate, police dispersed a protest in Sixth October City using teargas.
Pro-Brotherhood marches have been a common sight on Fridays since the ouster of Morsi in July 2013.
Meanwhile, in Alexandria governorate police reinforcements were deployed in anticipation of planned protests by Brotherhood supporters.
The Israeli offensive has so far killed 265 Palestinians and injured at least 1, 920.