Niger will choose between two heavyweights in a presidential run-off vote on Sunday set to bring about the first democratic transition of power in the coup-prone country's history.

Niger struggles with a poor economy and with jihadist insurgencies that have spilled over from Mali and Nigeria. Despite these crushing burdens, the country is on track for a peaceful handover between elected presidents, its first since independence from France in 1960.

Outgoing President Mahamadou Issoufou's decision to voluntarily step down after two five-year terms was welcomed in a region where many leaders have tried to cling on to power.

"Handing over power in 2021 to a democratically elected successor... will be my greatest achievement," Issoufou has said.

His successor will either be his right-hand man and anointed successor Mohamed Bazoum or Mahamane Ousmane, who became the country's first democratically- elected president in 1993, only to be toppled in a coup three years later.

Ousmane, 71, is running for president for the fifth time since his ouster.


Both candidates are stalwarts of Niger's political scene, where only a few men have jostled for power over the last decade, forging alliances and breaking them just as quickly.

Winning votes alone has not always led to power in Niger -- there have been four military coups and six elections since independence.

But political alliances will loom large on Sunday, when Bazoum will be the strong favourite after winning 39.3 percent of the first round vote on December 27.

The 60-year-old former interior minister has already sealed the support of the candidates who came third and fourth in the first round.

"Bazoum has a coalition that is expected to win if the voting instructions of the parties which support him are respected by their activists," said Ibrahim Yahya Ibrahim of the International Crisis Group (ICG) thinktank. But, he cautioned, it was "very far from being won".

Ousmane took nearly 17 percent in the first round. He can count on the support of a coalition of 18 opposition parties called Cap 20-21 as well as Hama Amadou, who had previously been thought to be the most formidable candidate against Bazoum.

Amadou was ruled out from running due to a prison sentence for baby trafficking which he has slammed as politically motivated.

The opposition filed an unsuccessful appeal against the result of the first round, claiming fraud.

A diplomatic source, speaking on condition of anonymity, said the concern was not so much "unfair practices" but the ruling party's imposing electoral machine.

The elections "aren't perfect, at least they are elections," the source said.

- Vast challenges -

Bazoum has campaigned on continuity with the previous regime, which has promised development in a country struggling with the highest birthrate in the world -- an average of seven children per woman.

"To absorb this population growth would take incredible economic growth," a Western diplomatic source said.

Only 7.4 million of the country's 22 million population are eligible to vote on Sunday -- the rest are under-age.

An immense security challenge also awaits whoever emerges as victor.

A brutal jihadist insurgency is intensifying in the country's west, while Islamist militants from the Nigerian movement Boko Haram wage incessant attacks in the southeast.

Like its Sahel neighbours Mali and Burkina Faso, Niger is increasingly struggling to cope.

Hundreds of troops have been killed and hundreds of thousands of people have fled their homes.

A senior defence ministry official said that thousands of security forces have been deployed to protect voting day, "especially in areas prone to insecurity", while Niger's borders will be closed for 24 hours.

Polling stations will be open from 8 am to 7pm.