Morsi Opponents Flood Tahrir amid Rival Demos and Talks on Govt.

Opponents of Egypt's deposed Islamist president Mohamed Morsi packed Tahrir Square in their tens of thousands on Sunday to show the world his ouster was not a military coup but the reflection of the people's will.

Staged as a counter-demonstration two days after Islamist rallies exploded into deadly violence, the protest raised the stakes as the country's interim leaders struggled to put together a new government.

As the crowds grew, wave after wave of military aircraft skimmed over the capital, with one formation leaving behind long trails of smoke in black, white and red -- the colors of the Egyptian flag.

"We are on the street to show the world that it was a popular revolution and not a coup that overthrew" Morsi on Wednesday, said a beaming teacher who gave her name as Magda.

Many banners showed the protesters' anger with the United States for what they perceive as its support for Morsi, as well as American media coverage depicting his ouster as a coup.

"America shame on you! This is a revolution, not a coup!" read one, echoing a chant heard in Tahrir, again and again. Others carried portraits of army chief Abdel Fattah al-Sisi, the general behind Morsi's ouster.

President Barack Obama insisted overnight that the United States was "not aligned" with any political party or group in Egypt following Morsi's ouster.

"The future path of Egypt can only be determined by the Egyptian people," the White House quoted him as saying.

The Tamarod movement, which engineered the June 30 rallies that culminated in Morsi's overthrow, had led calls for people to gather at Tahrir and Ittihadiya presidential palace to "complete the revolution."

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" -- a slogan used widely on June 30.

There were similar scenes in Alexandria on the Mediterranean and in other major cities across the Arab world's most populous country.

Their Islamist rivals staged their own huge demonstrations in Cairo, where police armed with Kalashnikov assault rifles watched over the pro-Morsi demonstrators.

Carrying pictures of the deposed president, the Islamists erected barricades and set up checkpoints across the capital, where tens of thousands of them blocked the main road to the international airport.

Morsi's single year of turbulent rule was marked by accusations he failed the 2011 revolution that ousted autocratic president Hosni Mubarak by concentrating power in Islamist hands and letting the economy nosedive.

The rallies came as a coalition that backed Morsi's ouster wavered over the choice of Nobel Prize laureate Mohamed ElBaradei as interim prime minister to lead the country out of the bloody crisis.

In an interview published on Sunday, ElBaradei called for "inclusion of the Brotherhood in the democratization process."

"No one should be taken to court without a convincing reason. Former president Morsi must be treated with dignity," the former U.N. nuclear watchdog chief 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.

Salafi Islamists, who backed Morsi's overthrow, were holding out against ElBaradei's appointment, officials close to the talks told Agence France Presse.

Presidential adviser Ahmed al-Muslimani said ElBaradei remained the "strongest candidate".

"He is on top of the list of names," Muslimani told AFP.

But after another round of talks on Sunday, 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 polarization 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 overnight on 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 ouster.

Violence that killed at least 37 people following Friday's Islamist rallies came despite talk of peaceful protests, with Cairo and second city Alexandria the hardest hit.

The bloodletting continued, with gunmen on Saturday killing a Coptic Christian priest in the Sinai Peninsula and militants on Sunday blowing up a gas pipeline to Jordan as Islamists fired on the security forces.

Russia's President Vladimir Putin warned the stand-off threatened to degenerate into a civil war.

"Syria is already in the grips of a civil war, unfortunately enough, and Egypt is moving in that direction," news agencies quoted him as saying.