Some Nigerians are returning to the polls Sunday after technical and other problems prevented them from casting their votes Saturday for a new president for Africa’s most populous democracy.

"The whole process is an absolute mess," Preye Iti, 60, a civil servant, told Reuters. "I waited from 8:30 a.m. to 6:30 p.m. yesterday. Now I'm back here at 8:30 again."

President Muhammadu Buhari is stepping down after serving the maximum eight years or two terms as allowed under the country’s constitution.

About 90 million Nigerians are eligible to cast their ballots in the election that will also determine who will serve in the National Assembly.

Veteran candidates – Bola Tinubu, 70, a former Lagos governor from the ruling All Progressives Congress party, and former Vice President Atiku Abubakar, 76, from the main opposition Peoples Democratic Party – are being challenged by a third-party candidate, the Labour Party's Peter Obi, 61, who has support among young voters.

The election occurs as Nigeria is experiencing a cash shortage, widening poverty, high inflation and energy shortages.

In the past, Nigeria’s elections have been marred by electoral fraud and violence, but the presidential candidates promised this week to support a peaceful and transparent process.

Nigeria’s Independent National Electoral Commission has said the results of the election will be available in a few days.

Some information in this report came from Reuters and Agence France-Presse.