A jailed candidate facing baby-trafficking charges was among the top contenders to challenge Niger's President Mahamadou Issoufou for the country's top job, as voters started turning out for presidential and parliamentary elections.
Niger is electing a head of state on Sunday, as well as a new parliament, with President Issoufou hoping to secure a second five-year term. A total of 7.5 million people are eligible to vote, with results due within five days.
Known as the "Zaki" or "lion" in Hausa, the majority language in Niger, Issoufou, a 63-year-old mathematician and mining engineer turned politician, faces a total of 14 rivals including a particularly tough challenge from two former prime ministers and an ex-president.
Should he fail to snatch a first-round victory, his main rivals have struck a deal to back whoever scores highest among them in the hope of ditching the president.
Niger arrests military officers over 'coup plot'
One of the contenders heading the opposition pack is 66-year-old Hama Amadou, who is campaigning from behind bars after being arrested in November on his return from exile in France over his alleged role in a baby-trafficking scandal.
Amadou, a former premier and parliament speaker, heads the Nigerien Democratic Movement (NDM) whose members were tear-gassed by police earlier this month after gathering in their thousands to support the prisoner-candidate, known as "the Phoenix" for his ability to rise from the ashes.
"Amadou's supporters tell you that he has gained more popularity just because he is behind bars. They say he was already popular, but now more so," said Al Jazeera's Mohamed Vall, reporting from the capital Niamey.
"But if you talk to the government side they say he was given a lot of publicity and that he is wanted for a crime that here in Niger is punishable by many years in prison," he added.
Vall said President Issoufou believes he will win the elections in the first round.
"The problem in this election is that since the beginning of the democratic process in Niger in 1993... there has been many disruptions because of coups," Vall said.
"There has been no election that has been decided in the first round, but now President Issoufou says he bets he will win in the first round."
Vall said another leading contender was opposition leader Seini Oumarou, who is described as more popular and more charismatic and the main challenger now for the president
"He is not behind bars. He is free and spent the past few weeks campaigning for this election across Niger and he has a pedigree according to people here," Vall said.
Oumarou served as premier to charismatic president Mamadou Tandja, who was overthrown by the army in 2010 after 10 years at the helm.
Also among the favourites is Niger's first-ever democratically elected president, Mahamane Ousmane, 66, who is making his fourth bid to step back into the job since his 1993 election.
Defence remains a top budget priority in the impoverished nation, amid the threat of raids by armed groups in the remote north and attacks by Nigeria's Boko Haram group on the southeast border.