The trial of more than 1,600 people suspected of ties with Boko Haram was expected to begin in Nigeria on Monday behind closed doors, in the biggest legal investigation into the eight-year militant Islamist insurgency.
More than 20,000 people have been killed and 2 million forced from their homes in northeastern Nigeria during the insurgency, contributing to what the United Nations has said is among the world's worst humanitarian crises.
Nigeria's ministry of justice said last month the trial of around 1,670 people held at the Kainji detention facility would begin at the site, in the central Niger state, on Monday and would be presided over by four judges.