Supporters and opponents of Egypt’s president clashes in the northern port town of Alexandria after he assumed sweeping new powers, a clear show of the deepening polarisation plaguing the country.President Mohammed Morsi’s decree put himself above the judiciary and also exempted the Islamist-dominated constituent assembly writing Egypt’s new constitution from judicial review. Liberal and secular members earlier walked out of the body, charging it would impose strict Islamic practices.Fifteen people were injured in clashes between supporters and opponents of the president. The headquarters of Morsi’s Freedom and Justice Party headquarters in Alexandria was set on fire by protesters on Friday afternoon.Thousands of protesters began gathering in Cairo’s Tahrir Square around midday on Friday after Egyptian opposition leaders called for a "million man march” to protest against what they say is a coup by Morsi. "The opposition are united in a way that we haven’t seen for quite some time,” Al Jazeera’s Peter Greste reported from Tahrir Square, noting that even some of his political allies were denouncing what was widely viewed as a drift into absolute rule. The protesters argue Morsi "has radically overstepped the legitimacy they gave him earlier in the year,” Greste siad. There is outrage over the fact that far from encouraging democracy in Egypt, the expanded presidential powers go beyond  those held by toppled president Hosni Mubarak.Hundreds of Morsi’s supporters rallied outside the presidential palace to express support for the president.  Morsi on Thursday issued a declaration giving himself greater powers and effectively neutralising a judicial system that had emerged as a key opponent by declaring that the courts are barred from challenging his decisions.Morsi’s decree raises very serious human rights concerns, a spokesperson for the UN Human Rights Commissioner Navi Pillay said on Friday."We are very concerned about the possible huge ramifications of this declaration on human rights and the rule of law inEgypt,” Rupert Colville told a news briefing at the United Nations in Geneva. "We also fear this could lead to a veryvolatile situation over the next few days, starting today in fact.”‘Protecting the revolution’Morsi framed his decisions as necessary to protect the revolution that ousted Mubarak nearly two years ago and to cement the nation’s transition to democratic rule.The president’s decree, which dismissed Abdel Majid Mahmoud, Egypt’s prosecutor general, prompted opposition figure Mohamed El Baradei to accuse Morsi of usurping authority and becoming a "new pharaoh”, while other opposition figures on Friday called for nationwide protests