A polarised Egypt entered a second week of political crisis, as opponents and supporters of deposed president Mohamed Morsi held rival demonstrations in Cairo and cities across the country.
The rallies on Sunday came as a coalition that backed Morsi's removal wavered over the choice of Mohamed ElBaradei as interim prime minister.
This also comes two days after 30 people were killed and more than 1,000 wounded in demonstrations by tens of thousands of Muslim Brotherhood supporters and opponents.
Meanwhile, Ahmed Suleiman, Egypt's justice minister, submitted his resignation on Sunday to the Council of Ministers, Egyptian news agency MENA reported.
Suleiman will stay on in a caretaker role until the formation of a new cabinet, it said.
The Tamarod movement, which engineered even bigger protests on June 30 that culminated in Morsi's overthrow on Wednesday, led calls for people to gather at Tahrir and Ittihadiya presidential palace to "complete the revolution".
And the anti-Morsi crowd swelled in the iconic square as people poured in from sidestreets, some unfurling a giant national flag emblazoned with the words "Go away" - echoing a slogan used widely on June 30.
"Egypt had a revolution, not a coup," read a huge banner wielded by one set of demonstrators. Others carried portraits of army chief Abdel Fattah al-Sisi, the general behind Morsi's ouster.
There were similar scenes in Alexandria on the Mediterranean and other major cities.
Their Islamist rivals converged on Rabaa al-Adawiya mosque, Cairo University and the Republican Guard headquarters for rallies to support the "legitimacy" of Morsi's election in June last year and to "reject the military coup".
Carrying pictures of Morsi, they erected barricades and set up checkpoints in various parts of the capital. Some even forced the closure of the main road to the international airport.
Doubts over interim PM
In an interview published on Sunday, ElBaradei called for "inclusion of the Brotherhood in the democratisation process".
"No one should be taken to court without a convincing reason. Former president Morsi must be treated with
dignity," the ElBaradei told German news weekly Der Spiegel.
The official MENA news agency said on Saturday that caretaker president Adly Mansour had appointed ElBaradei, only for his office to later deny any final decision had been taken.
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Presidential adviser Ahmed al-Muslimani said ElBaradei, the former head of the UN nuclear watchdog, remained the "strongest candidate".
"He is on top of the list of names," Muslimani told AFP.
But by Sunday morning, after another round of talks, a senior Salafi politician said his Al-Nour party would not accept ElBaradei.
"Our position is simple. There are two reasons to reject ElBaradei: we need a technocratic economic figure; and we need to end polarisation on the street," said Nader Bakkar.
"We can't talk of national reconciliation and then make Morsi's most ardent opponent prime minister."
An official close to ElBaradei conceded there were fears of alienating Al-Nour, which won almost a quarter of votes in a 2011 parliamentary election, and "driving them" into Morsi's camp.
Morsi, who has been in custody since Wednesday, had issued a defiant call for his supporters to defend his "legitimacy" as Egypt's first freely elected president, in a recorded speech released shortly after his removal.