Muslim Brotherhood candidate Mohammed Mursi claimed victory on Monday in Egypt's divisive race for the top job, as a military power grab overshadowed the country's first post-Mubarak presidential election.
Two generals from the Supreme Council of Armed Forces (SCAF), however, reiterated that the ruling body will transfer power to the new president by June 30 and insisted that he will enjoy full presidential powers.
A confirmed win by Mursi would mark the first time Islamists have taken the presidency of the Arab World's most populous nation, but military moves that appeared to render the post toothless were slammed by activists as a coup.
The Islamists' rival Ahmed Shafiq, a former air force chief and ex-prime minister to ousted president Hosni Mubarak, disputed the The Muslim Brotherhood's victory announcement, labelling it "bizarre behaviour."
State media also reported that initial counts showed Mursi ahead, however.
"After the counting was finished in all of Egypt's 27 provinces, indications show that Mohammed Mursi has won 51 percent and Ahmed Shafiq won 49 percent," the state-owned Al-Ahram said on its website.
There were scenes of jubilation at Mursi's Cairo headquarters, where the candidate thanked Egyptians for their votes in brief remarks after the Brotherhood said he had secured 52 percent of the ballots cast.
Mursi pledged to work "hand-in-hand with all Egyptians for a better future, freedom, democracy, development and peace."
"We are not seeking vengeance or to settle accounts," he said, adding that he would build a "modern, democratic state" for all Egyptians, Muslims and Christians alike.
A Shafiq campaign official disputed the Brotherhood victory claim, saying their figures showed its man was ahead.
"We reject it completely," Mahmud Baraka said of the Brotherhood claim. "We are astonished by this bizarre behaviour which amounts to a hijacking of the election results."
Mursi supporters, many tearful, screamed with excitement as several hundred people staged a victory rally in Cairo's iconic Tahrir Square, the hub of protests that led to Mubarak's departure in February 2011.
But their jubilation was overshadowed by the prospect of a looming showdown between the Brotherhood and the ruling military, which granted itself sweeping powers.
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"The military hands power to the military," read the headline of the independent daily Al-Masry al-Youm.
"A president with no powers," said another independent, Al-Shorouk.
Revolutionary youth movements, which had been split over whether to boycott the election or to vote Shafiq out, denounced the declaration as a "coup," while the Brotherhood's Freedom and Justice Party said it rejected any military bid to retake legislative power.
"The military council, with its unconstitutional coup, gave itself (unprecedented) powers. The military council has never and will never recognise popular legitimacy that contradicts it," the Coalition of Revolution Youth said in a statement.
"The next phase is a very difficult phase," senior Mursi campaign official Khaled al-Qazaz told AFP.
"It already started with the military trying to take all power, which requires all Egyptians to continue the momentum of the revolution to make sure the transition is complete."
The Brotherhood, which was accused of monopolising politics after last year's revolt, now finds itself increasingly marginalised, and even faces a lawsuit challenging its legitimacy and legal status.
But the military insists it will transfer power to the new president.
The election victor will swear his oath before the constitutional court by "June 30, this month," Mahmduh Shahin, one of the ruling generals, told a news conference.
Another SCAF general, Mohammed al-Assar, said the vote winner will enjoy full presidential powers.
"The president of the republic will be vested with all the powers of the president of the republic," Assar told reporters.
The presidential election had deeply polarised the country, between those who objected to the Brotherhood's Islamist agenda and those who feared a return to the old regime under Shafiq.
But there is no reason just yet to believe that Egypt will become a strict Islamic state, some say.
"Parliament had an Islamist majority and the world did not collapse... If Mursi wins, Egypt will not turn into Afghanistan as some people imagine, but it can however remain undemocratic," Amr Shoubaki, an analyst with the Al-Ahram Centre for Political and Strategic Studies, wrote in Al-Masry al-Youm.
The Brotherhood mobilised its formidable network of supporters to garner tallies from polling stations across the country and deliver early unofficial results, but the final official figures are not expected until Thursday.