Displaced people in north-east Nigeria have told the BBC they were transported through a dangerous conflict zone ahead of the country's elections in an operation agreed by the main political parties.
The BBC has been told that the unescorted convoys were organised with the agreement of both the ruling and main opposition parties, and the electoral commission.
Several thousand displaced people are believed to have been moved back to their home areas temporarily in order to vote.
Nigerians had been due to vote on 16 February but the polls were postponed until this Saturday.
Several witnesses described how displaced people had been organised into what they said was an unescorted convoy to make the journey from Maiduguri, the capital of Borno state, to the town of Monguno - a journey of 140km (87 miles) through territory which is known for attacks by Boko Haram and Islamic State in West Africa (Iswap).
Over the years, violence across the state has driven thousands to seek shelter in Maiduguri. But this, say senior officials from both the ruling All People's Congress (APC) and the opposition People's Democratic Party (PDP) creates logistical difficulties for those organising these elections because they would have to provide separate voting centres for each displaced group.