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.
Explosion hits US embassy in Oslo, causing minor damage, thick smoke
The U.S. embassy in Oslo was hit by a loud explosion early on Sunday, causing minor damage but no injuries, Norwegian police said.
Four killed in Beirut hotel strike, Israel says it targeted Iranian commanders
At least four people were killed when an Israeli strike hit an apartment in the Ramada hotel building in central Beirut early on Sunday, with Israel saying it targeted Iranian commanders operating in the Lebanese capital.
Drone attacks cause major fire at Kuwait International Airport
Two fuel depots at Kuwait International Airport came under a drone attack on Saturday night, causing a large fire at one of the facilities.
Israel warns Lebanon of 'heavy price' as week's death toll nears 300
Israel has warned Lebanon of a "very heavy price" if it did not rein in Hezbollah on Saturday, as it pounded the group's strongholds around the country with air strikes and mounted a deadly airborne raid in the east.
Trump rejects settling war with Iran
US President Donald Trump on Saturday has raised the possibility of the war against Iran ending only once that country no longer has a functioning military or any remaining leadership in power.
UAE air defences are currently responding to "incoming missile and drone threats", according to alerts from the Ministry of Defence and The National Emergency Crisis and Disaster Management Authority (NCEMA).
Dubai authorities have confirmed that debris from an aerial interception fell onto a vehicle in the Al Barsha area, resulting in the death of a driver.
President His Highness Sheikh Mohamed bin Zayed Al Nahyan said the UAE will "emerge stronger than before", affirming that the safety and security of citizens, residents, and visitors remain a top priority.
