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.
Israeli strikes kill 8 people in Gaza, medics say
Israeli strikes have killed at least eight Palestinians, including five police officers, in the Gaza Strip in two separate attacks on Sunday, according to medics and the interior ministry.
Crew from NASA's simulated Mars mission emerges after 378 days in isolation
The four members of a crew who took part in a simulated mission to Mars have emerged after 378 days in isolation at the US space agency's Johnson Space Center in Houston, an endeavor designed to help prepare for a possible future excursion by NASA astronauts to Earth's planetary neighbor.
Thousands join Indian opposition protest demanding poll chief's resignation
Thousands protested in Delhi on Sunday to demand the resignation of India's election chief over a revision of voter lists, the latest in more than a month of opposition demonstrations challenging Prime Minister Narendra Modi.
Iranian negotiators continue talks in Doha aimed at ending conflict
Iranian negotiators were in Doha on Sunday for a third consecutive day of discussions with Qatari mediators aimed at reaching a deal to end the conflict involving Iran, the United States and Israel.
His Highness Sheikh Mohammed bin Rashid Al Maktoum, Vice President and Prime Minister of the UAE, has announced the launch of Nad Zabeel, Dubai’s future research, design, and innovation campus that aims to attract 30,000 researchers and specialists.
His Highness Sheikh Khaled bin Mohamed bin Zayed Al Nahyan, Crown Prince of Abu Dhabi, has met with global leaders in energy, technology, artificial intelligence, and investment participating in ENACT Majlis, held at the Abu Dhabi Energy Center on Sunday.
Sharjah Charity International (SCI) has airlifted 140 tonnes of aid to the Gaza Strip under its “Warm Winter for Gaza” campaign.
