The Wednesday rallies were organized by a coalition of anti-government groups and activists, known as the Anti-Coup Alliance.
In the capital, Cairo, demonstrators chanted slogans against the rule of former army chief and current President Abdel Fattah al-Sisi and in support of ousted leader Mohamed Morsi.
Elsewhere in northern Sinai, protesters called for a huge rally on the anniversary of the January 25 revolution.
They also condemned the government's crackdown on dissent and called for the immediate release of political detainees.
Egypt has been the scene of massive anti-government protests, with continuous clashes between security forces and supporters of Morsi.
Morsi was Egypt’s first democratically-elected president, and was ousted in July 2013 in a military coup led by al-Sisi, the then head of the country’s armed forces.
