Protesters marking two years since Hosni Mubarak's fall have been sprayed by water cannon and tear gas outside the presidential palace.
Demonstrations were also expressing their anger at Mubarak's elected successor, Islamist president Mohamed Morsi, Middle East Online reported.
The crowd at the palace was described by the Associated Press as small, however some protesters tried to cross a barbed wire barrier at the Ettihadiya palace gate.
Others chanted: "The people want to bring down the regime." Others threw stones.
They had also graffitied the palace walls "Erhal" or "Leave," the same chant heard in Tahrir Square during the uprising that led to Mubarak's ouster on Feb. 11, 2011.
Protester Ahmed Farghaly told Reuters:
"We may be few in numbers but we will not back down from fighting criminals dressed up in police uniform."
Hundreds more rallied outside the office of the country's chief prosecutor, throwing plastic bags filled with red liquid signifying blood spilled during clashes with security forces after Morsi took office last summer.
They were demanding justice for those killed.
And masked men blocked trains at a central Cairo subway station while others blocked traffic with burning tires in central Cairo.