Tensions are high in Egypt as election officials prepare to announce official results of the country's disputed presidential runoff vote on Sunday.

The secretary-general of Egypt's election commission, Hatem Bagato, said Saturday that commission head Faruk Sultan will announce the results at 3 p.m. local time Sunday.

Both Muslim Brotherhood candidate Muhammad Morsi and former prime minister Ahmed Shafiq have declared victory in the election for a successor to former leader Hosni Mubarak, who resigned last year after massive protests.

The results were supposed to be released on Thursday. But the election commission said it needed time to investigate fraud allegations by both candidates.

On Saturday, hundreds of Muslim Brotherhood supporters were in Cairo's Tahrir Square chanting their support for Morsi. They have been there day and night and have vowed to stay until results of the June 16-17 runoff election are announced. The political group also denounced what it sees as a military power grab.

On Friday, Egypt's ruling military council accused Shafiq, a Mubarak-era candidate, and Morsi of raising tensions by prematurely declaring victory.

Muslim Brotherhood officials have warned of a confrontation between the people and the ruling military if Morsi is not named the winner. Supporters of both men have threatened a backlash should their candidate lose.

The Supreme Council of the Armed Forces has carried out a series of moves aimed at solidifying its power, including the court-ordered dissolution of the Islamist-dominated parliament.

The council also declared an interim constitution that gives its generals and the courts final say over much domestic and foreign policy, as well as the process to create a new, permanent constitution.

The council has promised to hand over power to civilian leadership by July 1, a claim many protesters fear will not happen.