(CBS/AP)-- Egypt's emergency services say 110 people have been injured in clashes between police and protesters during rallies marking the second anniversary of the revolution that toppled Hosni Mubarak's regime.
Two years after Egypt's revolution began, the country's schism was on display Friday as the mainly liberal and secular opposition held giant rallies, denouncing Islamist President Mohammed Morsi and saying the goals of the pro-democracy uprising have not been met.
The two sides clashed throughout the day in Cairo, Alexandria, the cities of Suez and Ismailia on the Suez Canal and a string of others, with police firing tear gas and protesters responding with stones.
A statement by the emergency services did not give details on the types of injuries or specify in which cities they took place.
The clashes pointed to Egypt's volatility and divisions nearly two years after Mubarak's ouster, with the country now defined by a struggle between ruling Islamists, and mostly secular and liberal opponents who say Islamists are moving to take complete power.
Thousands filled Cairo's central Tahrir Square, where the January 2011 uprising was born, and the area outside the presidential palace in the city's Heliopolis district. Throughout these places, the iconic Arab Spring chants of "Erha! Erhal!" or "leave, leave" and "the people want to topple the regime" rang out.
The protesters are using the anniversary to stage a show of strength in a bid to force Morsi to amend a disputed constitution drafted by his Islamist allies. They are also demanding freedom of expression and the independence of the judiciary.
Morsi's Muslim Brotherhood supporters opted not to mark the anniversary on the streets, arguing that they will honor the occasion with acts of public service, like treating the sick and planting trees, a tactic dismissed by the opposition as a public relations stunt ahead of parliamentary elections expected in April.
The Brotherhood's ultraconservative allies, known as Salafis, also said they would stay off the streets to avoid clashes.
The anniversary of the revolution comes as Egypt faces a new phase in its upheaval: Ruling Islamists trying to push through their agenda, an opposition trying to break their lock on power, and an economy in free-fall that threatens to fuel public discontent.
At the heart of the country's political divide is a disputed constitution drafted by Morsi's allies without the participation of liberals or minority Christians, what the opposition sees as a bid by Morsi and his Muslim Brotherhood to take control of all state institutions and the president's meddling in the judiciary.
"I am asking everyone to go out and demonstrate to show that the revolution must be completed and that the revolution must continue," opposition leader Mohamed ElBaradei said in a televised message posted on his party's website. "There must be a constitution for all Egyptians. A constitution that every one of us sees himself in it," said the Nobel peace Laureate and former head of the U.N. nuclear watchdog, IAEA.
New militia-like groups opposed to the Islamists have declared in video messages posted on social networks this week their intention to defend the opposition protesters if attacked. At least 10 people were killed and hundreds injured when Morsi's supporters descended upon protesters camped outside his palace in December, starting clashes that lasted for hours with firebombs, swords, knifes and firearms.