"In Egypt, there is the Muslim Brotherhood on one side and the rest of Egyptians on the other," says Mahmud Badr, who founded a campaign for the resignation of Islamist President Mohamed Morsi.
Badr said his campaign, dubbed Tamarod (rebellion in Arabic), had collected more than 15 million signatures in support of a snap presidential election just a year after Morsi took power.
Several opposition groups, including the National Salvation Front (NSF), have rallied around Tamarod and joined its call for mass protests on June 30 to coincide with the anniversary.
In just a matter of weeks since its launch, Tamarod is on everyone's lips and its members are seen collecting signatures all around the country.
It has capitalised on the low spirits caused by a severe economic crisis, fuel shortages, power cuts and soaring inflation to win support for its campaign to bring down Morsi and his Muslim Brotherhood, which it accuses of monopolising power.
But the campaign has also deeply divided the public.
Morsi's supporters say he is an elected president who is working to root out decades of corruption in state institutions. Any attempt to remove him from office would be a coup against democracy, they say.
His opponents accuse him of concentrating power in the hands of the Muslim Brotherhood and of failing the aspirations for freedom and social justice that inspired the revolution that toppled Hosni Mubarak in 2011.
"Collecting signatures for or against the president has no binding legal impact. It's political pressure, no more," said Judge Mohammed Hamed, the former head of the State Council -- a judicial body that groups several administrative courts.
Badr said Tamarod was launched because "Morsi has failed the country politically, economically and socially and has been unable to achieve the goals of the revolution.
"Tamarod did not create this polarisation, it existed long before. Tamarod grouped Egyptians of all segments around the idea of getting rid of Morsi," he said.
Shopkeeper Ismail Amr said he voted for Morsi in the June 2012 presidential election.
But he said he signed the Tamarod petition "because Morsi didn't keep his promises."
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Tamarod hopes its petition will eventually lead to Morsi's resignation, the handover of power to the head of the Supreme Constitutional Court and the formation of a government of technocrats -- something Morsi's supporters roundly reject.
Morsi said he will act decisively against "those who think they can destroy stability", accusing remnants of Mubarak's regime of trying to steer the country towards violence and chaos.
Analysts said there was a risk the polarisation could lead to military intervention.
Ahmed Abd Rabbo, a political science professor at Cairo University, warned it would be "the end of democracy in Egypt if Morsi falls and the army takes power."
Last week, the Muslim Brotherhood gathered tens of thousands of supporters "to defend the legitimacy" of the elected president.
Islamist parties have called for mass protests next Friday under the slogan "legitimacy is a red line."
The political divide has also taken on religious overtones. Salafist leader Mohamed Abdel Maqsud described those who opposed Morsi as "unbelievers", to the raucous applause of thousands at a conference attended by the president.
Sunni Islam's highest seat of learning, Cairo's Al-Azhar, said peaceful opposition was allowed but "has no links to religion."
May Mougib, professor of political science at Cairo University, warned: "If there are no confrontations on June 30, they will come later because the polarisation only needs a spark to explode."
Memories of bloody clashes between Morsi's supporters and opponents in December are still fresh in the minds of many Egyptians, causing mounting anxiety in the run-up to the weekend's demonstrations.
"I'm scared about June 30. I won't let my children take to the streets that day," one mother in her fifties told AFP.
On Sunday, Egypt's defence minister warned that the army will intervene if violence breaks out.
"The armed forces have the obligation to intervene to stop Egypt from plunging into a dark tunnel of conflict and infighting," Abdel Fattah al-Sisi said.
He urged Egyptians to set aside their differences, saying it was the army's duty to act to prevent chaos.
"It is the national and moral duty of the army to intervene... to prevent sectarian strife or the collapse of state institutions."