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.
Storms from Dolphin soak China's east, disrupt life in Shanghai
Torrential rain and storms in Typhoon Dolphin's wake have swept through several provinces in China's east, drenching the coastal region and flooding streets in Shanghai, the country's second most populated city.
Ukraine kills 13 in drone strikes on Russian city of Nizhnekamsk, officials say
At least 13 people were killed and 39 injured in a Ukrainian drone attack on industrial and civilian targets in the city of Nizhnekamsk, authorities said on Monday, one of the heaviest civilian tolls in Russia in months.
Yemeni military says Houthi attack on Mocha kills 7, wounds 30
The Yemeni military has announced early on Monday that seven people, including military personnel and civilians, were killed and 30 others wounded in a Houthi attack on the Red Sea port city of Mocha.
Gunman fires inside Thai government office as country reels from school shooting
A gunman was arrested after firing shots at a local government office on the outskirts of Thailand's capital on Monday, officials said, just days after a teenager's killing rampage at a school in the same province reignited debate over gun control.
Congo says number of confirmed Ebola cases rises to 4,120
The Government of the Democratic Republic of Congo (DRC) has raised the number of deaths to 1,887 and confirmed Ebola cases to 4,120 on Sunday due to the outbreak that was declared in the east of the country on May 15.
