- The development comes after election observers criticised INEC and the running of Saturday's vote, as well as presidential and parliamentary polls on February 23.
- Local elections are fiercely contested in Nigeria, as powerful governors generally have more impact on ordinary people's day-to-day lives than presidential and parliamentary votes.
Nigeria's electoral board said Tuesday the outcome of governorship polls in six states was inconclusive, sparking opposition fury and raising the prospect of re-runs and legal action.
It said violence and other irregularities had prompted voting Saturday to be cancelled in some areas of Kano and Sokoto, in the northwest, Bauchi and Adamawa in the northwest, and the central states of Benue and Plateau.
"We have concluded elections in 22 states. We have six states inconclusive and one suspended, that is Rivers," said Festus Okoye, from the Independent National Electoral Commission (INEC).
In areas where the poll was cancelled, the total vote exceeded the margin between the top two candidates, which prompted returning officers to declare the outcome for that state to be inconclusive, he told AFP.
"They did not satisfy the margin of lead principal as stated in our regulations and guidelines," he said.
The development comes after election observers criticised the organisation and the running of Saturday's vote, as well as presidential and parliamentary polls on February 23.
The European Union said on Monday there were "systemic failings and electoral security problems" in both that indicated a "real need for serious reform".
President Muhammadu Buhari's beaten rival, Atiku Abubakar, of the Peoples Democratic Party (PDP), called the vote a "sham" and is challenging the result in court.