President Alassane Ouattara's revised constitution, which parliament has overwhelmingly approved, would create a vice president picked by the president and establish a Senate in which a third of legislators would be nominated by the head of state. It would also end a clause - the so-called "Ivorian-ness" clause from 2000 - which stipulates that both parents of a presidential candidate must be born on Ivorian soil. Ouattara is from central Ivory Coast, but his father was born in neighboring Burkina Faso.

The president says the changes will help end unrest linked to issues of national identity. Violent episodes include a coup in 1999, a civil war in 2002 that split the country between its north and south, and a postelection crisis in 2010. The most recent violence led to months of bloodshed, with then-President Laurent Gbagbo refusing to step down.

The government claims that the idea is to ensure continuity in the event of a president's dying in office, but critics have speculated that Ouattara is trying to line up a successor for when his term ends in 2020. The opposition sees the change as a "monarchistic tactic."

US-based Human Rights Watch has warned that many Ivorians are not sure what they are voting for. "There is little engagement," said researcher Meite Mamoudou who, like many observers, expects that many people simply will not bother to vote.

Polling stations opened at 0800 UTC, but there were delays in some parts of Abidjan, the country's economic capital, because of a lack of equipment, including envelopes in which to place ballot papers. Voting closes at 6 p.m. An electoral commission source said the counting should be finished "by the end of Monday, Tuesday at the latest."

jbh/mkg (AFP, Reuters)