Citizens are going to the polls today after a last-minute postponement earlier this week.
The main challenger to reigning president Muhammadu Buhari is former Vice-President Atiku Abubakar.
It is not known exactly when the final results will be announced.
Experts say a winner could be declared as late as Tuesday.
Nigeria is Africa's most populated country.
Drone attack hits hotel in Baghdad Green Zone
Iraq's interior ministry said on Monday that a drone hit a hotel in Baghdad without causing casualties or material damages.
US allies rebuff Trump's request for support in Strait of Hormuz
Several U.S. allies said on Monday they had no immediate plans to send ships to unblock the Strait of Hormuz, rebuffing a request by President Donald Trump for military support to keep the vital waterway open.
Pakistan-bound oil tanker passes through Hormuz Strait amid Iran war
Ship-tracking data shows a Pakistan-bound oil tanker passing through the Strait of Hormuz over the weekend, indicating that some countries are able to negotiate safe passage for their vessels despite the US-Israeli conflict with Iran.
Iranian women's soccer team begin journey home after players decline asylum
The Iranian women's soccer team began making their way home from Malaysia on Monday, after five of its players withdrew their claims for asylum in Australia.
Israel says it has plans for at least three weeks of war as airstrikes pound Iran
Israel said on Monday it has detailed plans for at least three more weeks of war as its military countinued to pound sites across Iran.
