CAIRO - Egyptians must choose between a Muslim Brother and an ex-military man in a presidential run-off that highlights the stark rifts in a nation united in euphoria when Hosni Mubarak fell 15 months ago, first-round results indicated on Friday.
With most votes counted, the Muslim Brotherhood said its candidate Mohamed Mursi had topped this week's polls and would compete in next month's second round with former air force chief Ahmed Shafiq, who served as Mubarak's last prime minister.
The election marks a crucial step in a messy and often bloody transition to democracy, overseen by a military council that has pledged to hand power to a new president by July 1.
More turbulence could follow if Shafiq is elected and his foes have already vowed to take to the streets if that happens.
A victory for Mursi could worsen tensions between resurgent Islamists and the army, self-appointed guardian of the state.
Official results are only due on Tuesday, but a senior judge involved in supervising the vote said Mursi and Shafiq were in the lead, based on figures from 90 percent of polling stations.
Leftist Hamdeen Sabahy lay third, he said. The Brotherhood put Sabahy fourth behind another Islamist, Abdel Moneim Abol Fotouh, in a close race in which Mursi won 25 percent of votes.
A member of Shafiq's campaign also said Mursi and Shafiq were in the lead, but that counting was not complete.
The election has split Egyptians between those who oppose an effective return to the Mubarak era and those who fear an Islamist monopoly of ruling institutions.
The run-off will be held on June 16 and 17.
"Now Egyptians will have to choose between the revolution and the counter-revolution," Mohamed Beltagy, a leader of the Muslim Brotherhood's party, told Reuters.
But Islamists were slow to join the revolt against Mubarak and some of the youth who were at its forefront were aghast at the outcome of the first round and the choice they now face.
"To choose between Shafiq or Mursi is like being asked do you want to commit suicide by being set on fire or jump in a shark tank," Adel Abdel Ghafar wrote on Twitter, a networking tool used to devastating effect against Mubarak in the uprising.
Tareq Farouq, 34, a Cairo driver, said: "I'm in shock. How could this happen? The people don't want Mursi or Shafiq. We're sick of both. They are driving people back to Tahrir Square."