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.
Swiss prosecutors summon owners of ski resort bar after deadly blaze
Swiss prosecutors summoned on Friday the two owners of a ski resort bar where a fire on New Year's Day killed 40 people and a local newspaper said one of the couple had been detained, as calls grow for those responsible to be held to account.
Trump cancels second wave of attacks on Venezuela after cooperation
US President Donald Trump said on Friday he had cancelled a previously expected second wave of attacks on Venezuela following cooperation from the South American nation.
Widespread power cuts, travel disrupted as Storm Goretti hammers northern Europe
Storm Goretti battered northern Europe on Friday, knocking out power to thousands of homes, shutting schools and suspending rail services in France, Britain and Germany as heavy snow and gale-force winds compounded a week of freezing weather.
At least one killed, dozens missing in landfill collapse in central Philippines
At least one person was killed and 34 others were missing after a landfill collapsed in the city of Cebu in the central Philippines late on Thursday afternoon, officials said.
Trump says he will meet with Venezuela's Machado next week
US President Donald Trump has indicated on Thursday that Venezuelan opposition leader Maria Corina Machado was coming to Washington next week.
