The presidential candidate of Niger's ruling party looked set for a first-round win as his vote tally expanded on Friday.
Provisional results showed Mohamed Bazoum as having garnered 1.4 million votes, only trailed by former president Mahamane Ousmane with 675,000.
The electoral commission is expected to announce the final results Saturday in Niamey.
Former prime ministers Seini Oumarou and Albade Abouba were on course for 345,000 and 260,000 votes respectively.
The commission had provisionally earmarked Friday for the publication of the results but said this would now occur at 10 am (0900 GMT) Saturday at the Palais des Congres in Niamey.
Over two dozen sought Niger's presidency.
Insecurity overshadowed campaigning, with Niger attacked by extremists on its southwestern border with Mali as well as its southeastern frontier with Nigeria. Five years of violence have cost hundreds of lives with many more displaced.
Bazoum, 60, a former interior and foreign minister, hopes to clinch victory in the first round, which would be a first in the former French colony that also hopes to see a first peaceful handover between elected presidents.
Issoufou, who was elected in 2011 after the country's last coup in 2010, is voluntarily stepping down after two five-year terms.
In a New Year radio address, he hailed the election as "a new, successful page in our country's democratic history."
Bazoum campaigned on promises of emphasizing security and education.
If a second round proves necessary, it will take place on February 20.