Final results announced Sunday show that 77.2 percent of voters backed the changes in what was the freest vote in Egypt in more than half a century, despite reported irregularities.

The outcome sets the stage for a quick transition to a new government, as advocated by the military council that's been ruling Egypt since former President Hosni Mubarak was toppled by popular protests last month. But the truncated timeline means the new parties emerging in Egypt after decades of oppression could struggle to organize in time to find success in the elections. And opponents of the amendments say that the result gives unfair advantage to the two political groups that gained the deepest roots during Mr. Mubarak's regime: the Muslim Brotherhood and the former ruling National Democratic Party.

The vote is disappointing for Egyptian Christians, who had campaigned against the amendments, and could further strain sectarian tensions. They worried that a yes vote would allow the Muslim Brotherhood and other Islamists to gain a strong position in the coming parliament. The Muslim Brotherhood made a large effort to mobilize voters to cast ballots in support of the amendments.

Emad Gad, an analyst at the Al Ahram Center for Political and Strategic Studies, says Islamist factions will likely do well when parliamentary elections are held. “We can deal with this option if they will continue in power for four years only,” he says. “The main problem here is the next parliament will write the next Constitution. So then the fanatics and the Muslim Brotherhood will govern us for decades.”

The approved amendments, meant to amend the current Constitution just enough to allow fair elections before a new document is written, will limit the president to two four-year terms, force him to appoint a vice president, and curb his power to rule by emergency law. Opponents had argued that the changes don’t go far enough, and wanted a completely new Constitution before any elections were held.