Egypt is heading for a divisive run-off vote in its landmark presidential election, with the two most controversial candidates leading the race.
With close to 90% of the votes counted , the Islamic Muslim Brotherhood predicts that its candidate, Dr Mohammed Morsi, will emerge with the largest share.
Ahmed Shafiq, the last prime minister to serve under ousted president Hosni Mubarak, is set to take second place.
If the results are confirmed, it will mean both candidates will compete in a run-off vote in June, giving Egyptians a stark choice between an Islamist president and a leader from the old regime.
Some revolutionary activists have already described the outcome as the "nightmare scenario" for Egypt and predicted more protests and unrest.
The Muslim Brotherhood , which has dominated politics in Egypt since the revolution, was always expected to do well.
But Shafiq's success in the election - contested by 13 candidates - has surprised and horrified many Egyptians who had hoped they had seen the back of the old regime.
His main rival for the secular vote, 75-year-old Amr Moussa, has performed much worse than expected.
Mr Moussa, former head of the Arab League, presented himself as a critic of Mubarak, despite serving as a foreign minister in his government.
Former Air Force commander Mr Shafiq is thought to have attracted support from the security forces and those Egyptians unnerved by the revolution.
He is promising to restore stability to the country and guarantee a strong continuing role for the military, which has been ruling Egypt since the uprising in February 2011.
The Muslim Brotherhood wants Egypt to be governed according to Sharia law and already dominates the country's parliament.
Winning the presidency would give it sweeping power.
The movement claims to represent a "moderate" brand of Islam and has pledged to protect women's rights and those of minorities.
But for liberal Egyptians, particularly the young protesters who joined the Tahrir Square uprising, the choice is a return to the politics of the old Egypt.
The Mubarak era was defined by a struggle between conservative Islam and repressive secular rule.
The official election results are due to be announced on Tuesday.