The runoff vote to choose a new president was marred when seven electoral commission officials were killed after their vehicle hit a mine.
Nigeriens went to the polls on Sunday in the second round of the country's presidential election. It's expected the vote will pave the way for Niger's first democratic transition of power since independence from France more than six decades ago.
The vote was called after outgoing President Mahamadou Issoufou announced he was voluntarily stepping down after two five-year terms. "I'm proud to be the first democratically elected president in our history to be able to pass the baton to another democratically elected president," said Issoufou as he voted in the capital city of Niamey.
The two candidates to replace him are political stalwarts in the West African nation, which is one of the poorest in the world.
Thousands of soldiers were deployed, to ensure a peaceful transfer of power. Election results are expected in several days.
Who is running?
Mohamed Bazoum, Issoufou's right-hand man, is widely seen as the favorite after winning 39.3% of the vote in the first round. He has vowed to continue Issoufou's policies, with a focus on security and revamping the economy. He has the backing of the candidates who came third and fourth in the first round.
He is running against Mahamane Ousmane, who was the country's first democratically elected president in 1993 only to be toppled in a coup three years later. He won 17% of the votes in the first round and has the endorsement of about a dozen smaller parties and candidates. He has vowed to implement change and tackle corruption.
Ousmane also expressed concerns about electoral fraud.
"The suffrage of the citizens must be respected," Ousmane told reporters after he voted in the city of Zinder. "If citizens ever find out that these elections have been rigged again, I fear that the situation will be difficult to manage," he added.
Ousmane appealed for a transparent election so that citizens have their voices heard, stressing that people are "no longer willing to tolerate rigged elections."
Several dead in vehicle blast
At least seven people were killed after a vehicle belonging to Niger's electoral commission hit a landmine, marring what was meant to be a historic day.
The blast took place in the rural commune of Dargol in Tillabery region, some 100 kilometers (60 miles) from Niamey in the so-called tri-border region where Niger, Mali and Burkina Faso converge. One man was arrested, and polling stations in the area were closed, said authorities.
At least three more people were left seriously injured.
"This is a painful moment. It is a great shock for us, for us all," said Interior Minister Alkache Alhada.
Relative 'calm' in southeast Niger
Magagi Ganda Aissa, a civil society member based in the capital Niamey, said that while she is "not aware" of any incidents of voting fraud in Niger's largest city, "There have been reports that armed people have arrived and seized ballot boxes in the interior of the country."
DW correspondent Marah Mahamadou said election day in the southeast city of Diffa -- close to the border with Nigeria -- was calm.
"We must admit that the vote went very calmly. At the beginning, there was a little fear, but nothing was reported. People everywhere went out to vote," she said.
What challenges do they face?
The Sahel nation has a population of 24 million and struggles with poverty, recurring drought, floods and two festering insurgencies. Militants linked to al-Qaida and the "Islamic State" (IS) armed group have carried out a series of attacks near Niger's western border with Mali and Burkina Faso, while Boko Haram has killed hundreds of people along the southeastern border with Nigeria.
One of Niger's few exports, uranium, has been hit by a drop in price in recent years, and the coronavirus pandemic has weighed on Niger's economy.
Political analyst Elhadj Idi Abou, based in Niamey, said the result could go either way and that turnout was expected to be high.
"For me, there is no favorite because this ballot is the most open and the outcome does not depend on alliances but on the citizens. Both candidates have the same chances," he told the Reuters news agency.
Niger is the poorest nation in the world, according to the United Nations' development rankings for 189 naitons. Only 7.4 million people of the country's population of roughly 23 million are eligible to vote, as the rest aren't yet old enough. The country struggles with the highest birth rate in the world.