Egyptians learn the winner of a divisive presidential election Sunday.

The official results were supposed to be released Thursday, but the election commission said it needed more time to investigate fraud allegations by both candidates — Muslim Brotherhood's Mohamed Morsi and former prime minister Ahmed Shafiq.

Egyptian officials have deployed extra security forces to Cairo streets and key state institutions ahead of the announcement of the election results scheduled for 3 p.m. local time.

Supporters of both men have threatened a backlash should their candidate lose.

Thousands of Egyptians held rallies in central Cairo late Saturday amid tight security to show support for both candidates.

Muslim Brotherhood supporters rallied in Cairo's Tahrir Square, the heart of the 16-month uprising, chanting their support for Mr. Morsi, while Mr. Shafiq's supporters gathered near the memorial of the unknown soldier.

Whoever wins, the new president will emerge with fewer powers than the candidates had expected when the army promised to hand over power to civilian rule by July 1.

The ruling Supreme Council of the Armed Forces recently 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.