Egyptian President Mohammed Morsi Saturday called for calm after clashes between his opponents and police left nine people dead and more than 400 injured, according to medical sources.
"I call on all citizens to adhere to the noble principles of the Egyptian revolution in expressing opinion freely and peacefully," he said on his official Facebook page, dpa reported.
Responding to a call by the opposition, thousands of Egyptians held mass protests against Morsi and his Islamist-backed government Friday, marking the second anniversary of a revolt that toppled Hosny Mubarak.
Angry protesters torched offices of Morsi's Muslim Brotherhood and attacked governmental buildings in several areas across the country.
Police were engaged in sporadic clashes with protesters near the Interior Ministry headquarters and outside the state TV building in Cairo.
Morsi vowed that the state agencies would bring to justice what he called "criminals" involved in the unrest.
He offered condolences to families of the victims of what he termed "abominable violence."
The mostly secular opposition accuses Morsi, Egypt's first democratically president, of ruling at the Brotherhood's command, and of failing to revitalize an ailing economy.