In an exclusive interview with the Guardian, Morsi rejected opposition calls for early presidential elections and said he would not tolerate any deviation from constitutional order.
Thousands are on the streets (Archive photo: AP)
"If we changed someone in office who (was elected) according to constitutional legitimacy - well, there will (be) people or opponents opposing the new president too, and a week or a month later, they will ask him to step down," Morsi told the British daily.
"There is no room for any talk against this constitutional legitimacy," he said.
Waving Egyptian flags, crowds descended on Tahrir Square in the heart of Cairo, one of multiple sites in the capital and around the country where they plan rallies. Chants of "erhal!" or "leave!," rang out in the square, birthplace of the 2011 uprising that toppled autocrat Hosni Mubarak.
Morsi supporters (Photo: Reuters)
On the other side of Cairo, thousands of the Islamist leader's backers gathered not far from the presidential palace in a show of support. Some wore homemade body armor and construction hats and carried shields and clubs - precautions, they said, against possible violence.
Sunday marks the first anniversary of Morsi's assumption of power as Egypt's first freely elected leader.
Thousands of Morsi's supporters have staged a sit-in since Friday in an eastern Cairo district not far from the presidential palace, the focus of protests later on Sunday to demand his ouster.
Uncompromising. Mohammed Morsi (Photo: AFP)
The youth group leading the campaign to force Morsi out said it had collected more than 22 million signatures from Egyptians who want the president to go. It was not possible to verify the claim.
Morsi's supporters have questioned the authenticity and validity of the signatures.
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