Clashes erupted across Egypt on Friday as thousands took to the streets in anti-government protests to mark the second anniversary of the revolt that toppled Hosny Mubarak, dpa reported.
At least 119 people were injured in fighting between police and opponents of Islamist President Mohammed Morsi in Cairo in several larger cities, according to health officials.
Police said they had foiled attempts by angry protesters to storm security buildings and local government offices in several areas across the nation.
Security forces used tear gas to disperse Morsi' opponents after they broke through barbed wire barriers outside the presidential palace in eastern Cairo, reported the state-run newspaper al-Ahram online.
Protesters, meanwhile, blocked roads in Cairo and disrupted the city's metro service, said witnesses.
Other protesters attacked the office of Morsi's Muslim Brotherhood in the coastal city of Islamilia, reported local media.
Clashes also took place in the northern city of Alexandria after protesters surrounded and threw rocks at a local council building.
Police responded by firing shots in the air and using tear gas.
A group of protesters, identifying themselves as the Black Bloc, stormed a courthouse and blocked roads and tramways in the centre of Alexandria, Egypt's second-biggest city.
Violent clashes were also reported in the coastal city of Suez, leaving at least 41 people injured.
The opposition called for rallies against Morsi and the Brotherhood, accusing them of tightening their hold on power.
Thousands of Morsi's opponents converged on Cairo's central Tahrir Square - the epicentre of the 18-day revolt that ousted Mubarak in 2011.
They carried the Egyptian flag, pictures of people killed in previous protests and banners reading: "Down with the Brotherhood's constitution" and "The people want to topple the regime."
"I am taking part in marches today to reject the distorted constitution, Brotherhoodization of the state, a pounce on the rule of law and because the president and his government ignored the demands of social justice," liberal activist and former parliamentarian Amr Hamzawy said.
Egypt's new constitution, drafted by an Islamist-dominated assembly, was criticized by the opposition for language it says undermines political rights and sidelines minorities.
Morsi's opponents also staged mass demonstrations in other cities, which the opposition said were reminiscent of the protests against Mubarak two years ago.
Morsi's Islamist allies kept a low profile, saying they wanted to avoid clashes with his opponents.
"Today's demonstrations confirm the success of the January revolution, which has established the right of Egyptians to hold peaceful protests," Essam al-Erian, a senior Brotherhood official, said.
"The only way to end differences among political powers is dialogue or the ballot box," he told al-Ahram.
On the eve of the protests, Morsi called on Egyptians to mark the second anniversary of the revolt in a "civilized and peaceful way."
Morsi, Egypt's first freely elected president, faces the challenge of trying to revive the economy and ease tensions between Islamists and the secular-minded opposition.
On Thursday, Morsi blamed remnants of the Mubarak regime for trying to undermine stability.
"I hope all groups will remain peaceful during celebrations," Morsi said. "A structural reform is taking place in the state's institutions to fulfil the revolution's demands."