In the country's west, a vehicle carrying poll workers struck a landmine, killing seven and seriously wounding three others.
Media reports say a vehicle belonging to Niger's election commission struck a landmine in the rural community of Dargol.Ousmane, who was Niger's first democratically elected president in 1993, got only 17%.
"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," Issoufou said as he voted in Niger's capital, Niamey, according to Al Jazeera.