Voting started Sunday morning in the West African state of Niger where 15 candidates are vying for the presidency.
Incumbent president Mahamadou Issoufou is seeking a second five-year term.
About 7.5 million registered voters are also expected to elect 171 deputies to the country's National Assembly.
Most polling stations opened on time at 8 a.m. [0700 GMT] and are expected to close at 7 p.m. [0600 GMT], according to Anadolu Agency’s correspondent in Niamey, the capital.
Issoufou’s strongest opponents are Hama Amadou and Seyni Oumarou.
Amadou is currently in prison, accused of being involved in a child-trafficking case and jailed in November last year. His supporters say his imprisonment was politically motivated.
The opposition had earlier accused Issoufou of planning a “massive fraud” after he claimed he would win in the first round.
A second round of presidential voting will be held in March if no candidate secures a majority.
Issoufou, who is popular in some parts of the country for his fight against the Boko Haram militant group, is expected to win the presidential poll.
Issoufou came to power in 2011 following a coup in Feb. 2010. A military junta then appointed a transitional government, which later paved the way for Issoufou victory in a democratic election.
Niger, one of the poorest countries in the world, is also facing security issues, especially in the Diffa Region in the country’s southeast. This area has seen numerous Boko Haram attacks in recent months.
Niger is part of a Multinational Joint Task Force that was created by Lake Chad Basin countries -- Nigeria, Niger, Chad, Cameroon and Benin -- aimed at eradicating the militant group.