Egypt's Freedom and Justice Party, the political arm of the Muslim Brotherhood, announced early on June 18 that its candidate, Muhammad Morsi, has won the country's June 16-17 presidential election.
The announcement came via a posting on the party's Twitter account. The Muslim Brotherhood's website declared Mursi the "first popularly elected Egyptian president."
Appearing before supporters at his campaign headquarters, Morsi promised "to all Egypt in all its factions, Muslims and Christians,...to be a president for all Egyptians, a servant to them."
According to unofficial results, with 95 percent of polling stations counted, Morsi had 52 percent of the vote, while former Prime Minister Ahmed Shafiq had 48 percent.
Shafiq's campaign said it is "astonished" by the Brotherhood's victory declaration, adding that only the election commission can release vote tallies.
Meanwhile, the country's ruling Supreme Council of the Armed Forces on June 18 issued an amended "constitutional declaration" that arrogated to itself legislative authority and financial oversight.
WATCH: Muhammad Morsi declares victory
The document also says the council will appoint a 100-member body to draft a new constitution for the country and that new parliamentary elections will not be held until after the new constitution is approved.
The military council has confirmed that it plans to hand over power to the newly elected president by the end of the month.
Official media quoted a senior member of the military council, Major General Muhammad al-Assar, as saying the transfer of power will take place in a "grand ceremony."
He gave no exact date.
The military council is headed by Field Marshal Hussein Tantawi, who served as defense minister for 20 years under longtime Egyptian strongman Hosni Mubarak.
At a predawn press conference, Muslim Brotherhood spokesmen said the party does not recognize a recent court decision that declared the elected parliament invalid or the military council's constitutional declaration.
Supporters of the Brotherhood chanted, "Down with military rule!"
The presidential campaign was bitter and divisive. Many saw Shafiq, a former Air Force commander and Mubarak's last prime minister, as a continuation of the old regime despite the uprising that ousted Mubarak in 2011.
On the other hand, Morsi's detractors fear the Muslim Brotherhod intends to turn Egypt into an Islamic state and adopt policies curtailing the rights of Christians and women.
Unofficial results of the June 16-17 presidential election are expected early on June 18, but election officials say the official result of the poll will be announced only on June 21.
With reporting by dpa, AP, and AFP