Nigeria’s President Muhammadu Buhari on Friday sought to calm fears about election security, promising Nigerian voters they would be able to cast their ballots in safety.

“Do not be afraid of rumours of violence and unrest. Our security agencies have worked diligently to ensure that adequate security measures are in place,” he said.

“You will be able to vote in an atmosphere of openness and peace, devoid of fear from threat or intimidation,” he added.

Buhari, 76, is seeking a second term of office on Saturday, but is facing a strong challenge from the main opposition candidate, former vice-president Atiku Abubakar.

Previous elections have been hit by violence since the country returned to civilian rule in 1999 after decades of military government.

But tensions have increased since last Saturday, when the electoral commission postponed the vote just hours before polling citing logistical difficulties.

Buhari’s ruling All Progressives Congress (APC) and the main opposition Peoples Democratic Party (PDP) have accused the other of conspiring with the commission to rig the result.

Abubakar, 72, said Buhari was paying “lip service” to democracy after he revealed he had ordered security services to be “ruthless” with vote-riggers and ballot snatchers.

His opponent said the order — which won the backing of the army — was a “threat” and a “recipe for crisis”, while others said he was encouraging violence.

Just over 84 million people have been registered to vote on Saturday. Parliamentary elections will be held at the same time. Governorship and state assembly polls follow on March 9.

Abubakar said he is hoping for a repeat of 2015, when the opposition voted out the president for the first time in Nigeria’s history.