Thousands of Islamists flowed into Cairo's Tahrir Square to hear Egypt's president-elect make his first public speech since declaring victory in a clear bid to rally popular support as he faces a struggle for power with the country's ruling generals.
Morsi addressed the crowds, saying: "Free revolutionaries, together we will complete the path."
Morsi then took an informal oath of office in front of his supporters.
"There is no power above people power," Morsi declared to wild cheers from the crowd.
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Mohammed Morsi of the Muslim Brotherhood is the first Islamist and the first civilian to win the presidency, a job held for nearly three decades by Hosni Mubarak who was ousted by an uprising last year.
But he is already facing a serious challenge after the Mubarak-era military rulers who oversee the transition took a series of decisions undermining the powers of his office before his swearing-in, which was scheduled for Saturday.
His visit to Tahrir is also a nod to the protesters who supported his bid for leadership in a bitter campaign that pitted him against Mubarak's last prime minister Ahmed Shafiq.
Many protesters have called for Morsi to take the oath of office in the square, the epicenter of mass protests against Mubarak and later the continued military rule, but the ceremony was scheduled to be held Saturday before a high court.
His appearance in Tahrir a day before the official ceremony is clearly a nod to the calls for a popular oath.
Egyptians will be watching Morsi's statements to see whether he will accept the restrictions on his power or try to use his position as an elected president to force the military to lift them. His influence is hampered by a court decision that dissolved the country's first freely elected parliament, which was dominated by Islamists.
The ruling generals have promised to transfer power to an elected president by Sunday. But they also have given themselves sweeping powers that undercut the authority of the president. The constitutional declaration – issued days before the winner of a runoff vote was announced – also designated the generals the country's legislature in place of the disbanded parliament.
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