Tens of thousands have packed Cairo's iconic Tahrir Square to denounce a power grab by the ruling military, as the nation nervously awaited the results of the first post-Mubarak presidential election.
Yet Egypt's ruling military warned it would "deal firmly" with any attempt to harm the public interest, and blamed political divisions on the release of unofficial presidential poll results by candidates.
"Protecting the status of state institutions is a national responsibility for all: any attack on them threatens the stability and national security of Egypt," said a Supreme Council of the Armed Forces statement read on state television on Friday afternoon.
"Any attempts to harm public or private interests will be confronted with utmost firmness and strength by the police and armed forces within the law," SCAF said.
The SCAF defended a constitutional document giving it legislative powers, control over the new constitution and a broad say in government policy.
"The issuing of a constitutional declaration was a necessity imposed by the needs of managing the affairs of the country during the current critical phase of the history of our nation," the military council said.
It instead blamed the tension in Egypt on the release of unofficial poll results.
"The early release of the presidential election results, before the announcement by the responsible body, was unjustified and is one of the main reasons for divisions and tensions in the political arena," SCAF said.
Its comments appeared to be directed at the powerful Muslim Brotherhood, which said that its candidate Mohamed Morsi had won the election, providing what it said were certified copies of ballot tallies to bolster its claims.
'Neither confrontation nor violence'
Morsi held a subsequent press conference following the release of SCAF's statement, where he said the Brotherhood wants neither "confrontation nor violence".
But he added: "The expected result is known to everyone. We will not allow anyone to tamper with the result."
"We expect that the result will truly reflect the popular will, which we all know," said Morsi, adding that the thousands of protesters in Tahrir Square were there to "guarantee that will" is respected.
Morsi was speaking at a news conference in Cairo, flanked by several liberal and leftist figures.
He slammed a constitutional declaration issued by the ruling military council that granted the army sweeping powers, as well as the dissolution of parliament and a justice ministry decision giving soldiers powers of arrest.
"We reject all this... and the timing concerns us all," said Morsi.
But he pledged that his movement and supporters did not have any plans to clash with the military council or to instigate unrest.
"There will be no confrontation or violence or attempts to shake the stability of this country," he said.
"The protection of the nation is our highest goal, (including) the protection of its institutions, public and private property."
'Down with military rule'
Members and supporters of the powerful Muslim Brotherhood gathered in the square for the protest on Friday, which was to be joined later in the afternoon by several secular movements.
Protesters used umbrellas, newspapers and hats to shield themselves from the brutal sun, as they chanted "down with military rule."
Al Jazeera's Mike Hanna, reporting from Tahrir Square, said the crowds "dismissed the statement" released by the SCAF earlier in the day.
He went on to say that the crowd gathered in Tahrir were made up of different political supporters. "This is probably the most united display of protest seen for a long period of time."
"The Muslim Brotherhood has called for protesters to come here, but they have been joined the revolutionary socialists, and the salafi Al Nour party, so this is a wide expanse of political opposition expressed in the square."
Those camping out overnight demanded military rulers reverse new orders that entrench the generals' power and called on the election commission to declare the Muslim Brotherhood's Mohamed Morsi president.
Across town, in a luxury international hotel, former general Ahmed Shafik, who was Hosni Mubarak's prime minister when the army forced out the dictator to appease the Tahrir protesters, challenged Morsi's self-proclaimed victory and said he was sure he had won.
At a televised address to whooping and cheering supporters, Shafik said: "These protests in the squares, the campaigns of terror and the media manipulation are all attempts to force the election committee to announce a particular result."
Speaking in person rather than through spokesmen as he has through the week, he added: "I am fully confident that I will be the legitimate winner." He called for calm and unity, saying he would invite opponents to join his administration.
On Thursday, Human Rights Watch (HRW) said it held concerns over the military's commitment to hand over power to civilian rule.
"The generals' relentless expansion of their authority to detain and try civilians now goes far beyond their powers under Hosni Mubarak," Joe Stork, HRW Middle East director, said in a statement
"These decrees are the latest indication yet that there won't be a meaningful handover to civilian rule on June 30," Stork added.
The Election Commission did not say when it would announce the winner of the runoff. But its secretary-general, Hatem Begato, told the state newspaper Al-Ahram that the winner would be announced on Saturday or Sunday.
Allegations of fraud
The commission said the announcement was postponed from Thursday because a panel of judges must look into about 400 complaints of voting fraud submitted by both campaigns, including lawyers for Shafik claiming fraud in 14 of Egypt's 27 provinces.
The lawyers said ballots sent to polling centers were already marked for Morsi.
Morsi's lawyers accused Shafik of buying votes and being involved in forging lists of registered voters to include soldiers, who are barred from voting, and names of the dead.
The Brotherhood says it is being targeted by an organised campaign to keep it out of the presidency, and that even if Morsi is declared the victor, he will face deep resistance that will make it impossible for him to govern.
After two days of voting that ended on Sunday, the group declared Morsi won 52 per cent of the vote. Shafiq's camp on Monday announced he had won 51.5 per cent of the vote.