For the first time in more than 41 years, Gabonese casting their votes Sunday will not know ahead of time who their next president will be.

Eighteen candidates are vying to replace the late President Omar Bongo, who ruled for more than four decades and ran as the only candidate in many elections. But some critics say it is too soon to declare democracy in the tiny, oil-rich coastal nation.

The leading contender in Sunday's race is Ali Bongo Ondimba — the dead ruler's eldest son. He has put up posters of himself every 30 feet (9 meters) on the capital's main highway and has crisscrossed the heavily forested country in a private jet to campaign.

Still, it's not a foregone conclusion that he will win, and for once Gabon's future leader is an open-ended question.

"This is a historic moment. It's the first time since the 1960s that we don't know what the outcome of this election will be. It's also the first time since the 1960s that the name 'Omar Bongo' doesn't appear on the ballot," said Anacle Bissielo, the country's minister of development and a sociology professor at Omar Bongo University in Libreville.

The Senate leader and interim president, Rose Francine Rogombe, urged Gabonese to "vote calmly, and then go stay at home ... don't take to the streets."

Lines of people snaked out of polling stations including at the Kingulele Public School in the capital, where some 200 citizens waited as a military convoy delivered boxes of polling materials.

"It's my first time voting, and I need to vote," 23-year-old Jacques Koumba said. "I need to make up for the past 40 years."

The race is shaping up as a contest between the 50-year-old Ali Bongo and four opposition candidates, out of a total 18 running. Pierre Mamboundou, who has been at the vanguard of the country's opposition for 20 years and was once exiled to Senegal after the elder Bongo accused him of plotting a coup, is seen as an attractive choice to those calling for wholesale change.

Other leading candidates include former Interior Minister Andre Mba Obame, who has been a member of the ruling Gabonese Democratic Party and is backed by five independents who dropped out of the race, and Cassimir Oye Mba, who left the Gabonese Democratic Party after it nominated Ali Bongo as its candidate. One of his campaign pledges is to build 100 kilometers (60 miles) of road a year.

None of the 18 candidates has a majority of support, however, and it is unclear whether a winner will be declared even without winning more than 50 percent of the vote.

But some voters said they were dissatisfied with their choices and held little hope for change in Gabon, where one-third of the population lives in population lives in poverty so dire that some residents of the capital, Libreville, dig through the trash dump to feed their children.

Much of the rest of the country is cut off from Libreville by thick jungle and is reachable only by plane.

"Why vote when our life conditions are not going to change?" said Rolande Boelingui, 27, after voting in the city's 4th district. "We are still hungry. All the candidates are making the same promise. But they never make good on their promises."

Gabon was a leading oil producer in the 1970s. The elder Bongo, who died in June, is accused of wasting the oil wealth by building vanity projects such as a massive, marbled presidential palace and a little-used trans-Gabon railroad, instead of basic infrastructure.

He was also criticized for holding onto power for decades, running uncontested in some elections and dismissing allegations of fraud in others.

Many voters worried Sunday's poll would also be tainted by fraud. One opposition candidate has even gone on a hunger strike to protest what he calls an "electoral coup d'etat" by Ali Bongo and the ruling party.

Bruno Ben Moubamba, 42, who was rushed to the hospital last week after not eating for two weeks, has charged that the voter list is inflated. The list includes 816,000 names in a country of 1.5 million. Citizens' groups have collected evidence they say shows some voters were issued multiple voter registration cards.

Moubamba said he expects riots if Ali Bongo is declared the winner.

"Ali Bongo can't even win 5 percent of the vote in his native village," he said. "After 41 years, people are tired. They want a change. We are in a situation of latent violence. It's as if the whole country has been drenched in gasoline. All we need is one match."

Election Commission President Renee Aboghe Ella acknowledged that the voter list appears to be inflated, but said safeguards were in place to prevent people from voting more than once, even if they had multiple ID cards.

Another concern is that a winner may be declared without security a majority of the vote — a departure from many African political systems. Ella said the former president was so entrenched in the political landscape that he always got more than 50 percent.

"It could create a problem of legitimacy," he said. "It's the first time that we find ourselves in this situation."