Human Rights Watch says security forces are ignoring rights in dealing with threats.
Transnet and government officials said the global crash of crude prices was a temporary setback.
190 captives which included young men, women and children who were kidnapped, were released.
The situation in Maiduguri remains uncertain after attacks by suspected Boko Haram militants on two towns.
The 14 February elections will be the first where Nigeria’s 68.8 million voters must have a biometric cards.
Boko Haram is threatening the stability of the West African region.