Egyptians are voting in a two-day referendum to decide whether to adopt a new constitution supported by the military-backed interim government.
Security is high across the nation, and at least five people have died in clashes with police. Four Muslim Brotherhood supporters died in protests in the city of Sohag, south of Cairo. Several others were wounded, including a police officer.
A bomb exploded outside a courthouse in Giza before polls opened. No one was injured.
While Tuesday's vote is officially to approve or reject the constitution, VOA's correspondent in Cairo, Elizabeth Arrott, says the vote is really seen as a referendum on the man likely to run for president if the constitution is approved -- the country's army chief, who ousted Islamist president Mohamed Morsi in July.
"Many people are seeing this, really, as an endorsement of General Abdel Fatteh el Sissi, the defense minister who's really the de facto leader here. So it is about this constitution. It's the third in three years that they've gone to the polls for. Nominally. But it's more, it seems to be whether it's going to be an endorsement of the new ruling elite."
Arrott says the referendum is expected to pass, but the process has been marred by a crackdown on the opposition.
"It seems by all indications that it will pass. There's never been a referendum that has not passed in Egypt. So it's likely to. The opponents have been so harassed - mainly the Muslim Brotherhood, well they've called for a boycott - they're banned, and most of their leaders are arrested, so it's very hard to organize sort of opposition to it."
A group that includes Mr. Morsi's Muslim Brotherhood urged Egyptians to boycott the referendum and peacefully protest a process the group called illegitimate.
Saba Mahmood, associate professor of anthropology at the University of California at Berkeley told VOA she expects the document to be ratified by a "broad referendum."
"I think this is the result of two things. One is the political repression that the military government has unleased in Egypt so that most people who disagree with the government are not going to really come out in any great numbers because they are afraid of the political repercussions. And secondly, there is a general nationalist fervor that has gripped the country in support of the military."
The constitutional referendum comes about a year after Mr. Morsi signed the last constitution into law. The new proposed charter would strip out Islamist language in the existing document, give women greater rights and strengthen the power of the military.
A roadmap set by the military calls for parliamentary and presidential elections to follow later this year.
In Washington, the U.S. State Department Monday expressed concern about reports that people campaigning for a 'no' vote have been arrested.
Spokeswoman Marie Harf said the United States is deeply troubled by reports that at least one individual was beaten during his arrest.
Egyptians living abroad already have voted on the new constitution.
The military removed Mr. Morsi from power after opposition protests that accused him of trying to monopolize power. Authorities have since spent months cracking down on the Muslim Brotherhood, including arresting many of its leaders and declaring it a terrorist group.
More than 1,000 people, mainly pro-Morsi Islamists, have been killed, while protests continue.