Mr Lungu has been in power since 2015 and is seeking to extend his rule.
An estimated seven million people registered to vote in this year’s presidential and parliamentary elections.
President Buhari expressed his concern while condoling with the Nigerien president on the flooding disaster.
Among those to be repatriated are victims of human trafficking and those detained in Libyan prisons for migration offences.
Nigeria took delivery of 177,600 doses of the Johnson & Johnson vaccines on Thursday.
Conservationists are asking the government to ensure the elephant population is protected against unguarded exploitation by humans.
Madagascar President Andry Rajoelina has sacked all his ministers, his office said.
Sixteen names are on the ballot, but the election is expected to be a close call between incumbent Edgar Lungu and Hakainde Hichilema.
Among the defendants wanted by the ICC is former president Omar al-Bashir.
Mr Wabba said he was speaking in solidarity with Tunisian workers.
