Mursi's detractors dubbed him the 'new pharaoh', a day after he issued a declaration granting himself what many said were more powers than the ousted dictator Hosni Mubarak.
Thousands of his supporters and opponents today took to streets to stage rival rallies across Egypt, leading to sporadic violence and burning down of offices belonging to the ruling Muslim Brotherhood.
Amid much concern over the move, Mursi told his supporters that Egypt was on the path to "freedom and democracy," and stability was the need of the hour.
"Political stability, social stability and economic stability are what I want and that is what I am working for," he told an Islamist rally outside the presidential palace.
Mursi's new powers are supposed to be temporary, to last for the transition period, and the decree will expire when a new constitution is approved by the middle of February.
However his opponents see the move as endangering the gains of the popular uprising which ousted Mubarak's dictatorial
"I have always been, and still am, and will always be, God willing, with the pulse of the people, what the people want, with clear legitimacy," Mursi said.
The President's declaration also ordered retrials of officials involved in the killing of protesters during the 2011 mass uprising against the Mubarak regime.
Protesters marching from various city points converged in in Cairo's iconic Tahrir Square chanting slogans such as "Down with the Supreme Guide," "Wake up Mursi, it's your last day," and the popular "The people demand the fall of the regime."
The protesters held banners denouncing the Muslim Brotherhood and its intervention in the state policy, as well as banners rejecting yesterday's constitutional declaration.
During the protests, offices of the Freedom and Justice Party (FJP), the Muslim Brotherhood's political arm, were set ablaze in Ismailiya and Port Said, state television said.
It was also reported that the party's office in Alexandria was also stormed. Eyewitnesses said 15 were injured in the clashes as both sides hurled stones at each other, and at least five cars were smashed.
The protesters arrived in Tahrir about an hour after Islamist supporters of Mursi came out in the tens to demonstrate against the Constitution Party's anti-Mursi protest march.
The two groups engaged in verbal sparring matches, shouting slogans at each other after the Friday prayers.
The Islamist protesters chanted pro-Mursi slogans, such as "People want God's rules to be applied" and held Quran in their hands.
Arrangements began early morning for the protests, which were called by several political forces during a meeting at the Wafd Party headquarters late last night following Mursi's announcement.
Political forces including the Wafd Party, Tagammu Party, Constitution Party, Democratic Egyptian Party, Free Egyptians Party and Popular Trend Party, as well as the April 6 Youth Movement, the Revolutionary Youth Union, the Free Egyptian Movement, the No to Military Trials group and the Bring them for Trial campaign announced participation in the protest.
Meanwhile, Islamist forces including the Muslim Brotherhood, Jama'a al-Islamiya, and Salafi Dawah as well the Freedom and Justice Party, the Noor Party, Asala and Wasat were in support of the new constitutional declaration.
In Alexandria where the FJP headquarters was stormed and set ablaze, security head Abdel Meguid Lotfy said four Central Security Force teams were sent to secure it.
Reports set after setting ablaze an FJP office near Leader Ibrahim Square in Alexandria, protesters set another office in the al-Ibrahimeya district ablaze.
Amr al-Demerdash, the media coordinator for the revolutionary Kefaya movement, was injured in clashes with Brotherhood members outside the Leader Ibrahim Mosque.
He is reportedly undergoing cosmetic surgery for injuries he sustained to his face.
As clashes erupted, mosque leaders used speakers to urge the two groups to stop and disperse.
In Port Said where the Brotherhood office was attacked, protesters shouted anti Mursi solgans.
"Sell, sell the revolution oh Badei (the Brotherhood supreme guide)" and "Down with the supreme guide rule," they chanted as they blocked traffic.
The confrontations began when Muslim Brotherhood members and revolutionary activists engaged in a shouting match after the Friday prayer in front of the mosque.
Last night, presidential spokesperson Yasser Ali announced the constitutional declaration, saying it was aimed at ending governmental corruption.
Cairo: Egyptian President Mohamed Mursi assured his supporters that the country was on a path of "freedom and democracy" even as thousands of people staged rival rallies across the polarised nation to both support and oppose his move to assume sweeping powers.
First Published: Friday, November 23, 2012, 10:25