Abuja - Nigerians hit by failures in new election technology return to the polls on Sunday, to allow them to cast their ballots in the country's close-run presidential election.
President Goodluck Jonathan - who is running against former military ruler Muhammadu Buhari - and at least three governors from his ruling party were among those whose biometric details could not be checked by the devices, which are designed to combat electoral fraud.
Instead, they had to be processed by hand. Jonathan's Peoples Democratic Party (PDP) called it a "huge national embarrassment" and a "vindication" of their position against the technology.