Polls have opened in Egypt as the nation votes on amendments that would allow President Abdel Fattah el-Sisi to stay in power for another 11 years.
Egyptians are voting on constitutional amendments that would allow President Abdel Fattah el-Sisi to stay in power until 2030 and broaden the military's role - changes blasted by critics as another major step toward authoritarian rule.
The referendum came amid an unprecedented crackdown on dissent in recent years.
El-Sisi's government has arrested thousands of people, most of them Islamists but also prominent secular activists, and rolled back freedoms won in a 2011 pro-democracy uprising.
Voting will stretch over a period of three days to allow maximum turnout.
Casting his ballot on Saturday, Prime Minister Mustafa Madbouly urged voters to turn out in high numbers. He said that voting will reflect "the atmosphere of stability and democracy that we are witnessing now".
The state-run TV said el-Sisi had cast his vote in Cairo's Heliopolis district, nearby the presidential palace.
Opposition voices have largely been shut out amid the rush to hold the referendum. Pro-government media have led a campaign for weeks calling a "Yes" vote a patriotic duty.
Since early April, the Egyptian capital has been awash with large posters and banners encouraging people to vote in favour of the changes. Most of the posters were apparently funded by pro-government parties, businessmen and lawmakers.
Parliament, packed with el-Sisi supporters, overwhelmingly approved the amendments on Tuesday, with only 22 no votes and one abstention from 554 politicians in attendance. The national electoral commission announced the following day that voting would begin on Saturday.
The proposed changes are seen by critics as another step toward authoritarianism. The referendum comes eight years after a pro-democracy uprising ended autocrat Hosni Mubarak's three-decade rule, and nearly six years after el-Sisi led a popular military overthrow of the country's first freely elected but divisive Islamist president, Mohammed Morsi.
The amendments extend a president's term in office from four to six years and allow for a maximum of two terms. But they also include an article specific to el-Sisi that extends his current second four-year term to six years and allows him to run for another six-year term in 2024, potentially extending his rule until 2030.
El-Sisi was elected president in 2014 and re-elected last year after all potentially serious challengers were either jailed or pressured to exit the race.
The amendments also allow the president to appoint top judges and bypass judiciary oversight in vetting draft legislation, while also granting military courts wider jurisdiction in trying civilians.
In the last three years, over 15,000 civilians, including children, have been referred to military prosecution in Egypt, according to Human Rights Watch.
The amendments also introduce one or more vice presidents, revive the Senate and enshrine a 25 per cent quota for women in parliament's lower, legislative chamber. All three had been dropped from Egypt's constitution after the 2011 revolution.