Kano - Nigeria officially remanded 300 Boko Haram suspects on Tuesday as hearings got under way in the first mass trials linked to the Islamist insurgency.
The media has been banned on security grounds from attending proceedings at four civilian courts set up in a military base in Kainji, in central Niger state.
But the justice ministry said in an emailed statement that three separate cases, each involving 100 defendants, were heard in three of the courts.
Ministry spokesperson Salihu Othman Isah said the judges ordered all the defendants to be remanded for 90 days, pending further investigations and preparation of charges.
The hearings will resume on January 9, the judges ruled.
One defendant, who is accused of attempting to bomb the main mosque in the northeastern city of Bauchi, was ordered to be transferred to face trial.
A total of 1 669 suspects - 1 631 men, 11 women, 26 boys and one girl - are being held at the Kainji facility, pending formal charges and trial.
The government has said it then plans to prosecute 651 others held at the Giwa military barracks in the northeastern city of Maiduguri.
Observers have welcomed the prosecutions as a positive step, but lack of access to independent scrutineers has raised concerns about the transparency of the process.
The justice ministry itself has already said the trials could be affected by poor investigation techniques, a lack of forensic evidence and an "over-reliance" on confessions.
That raises the prospect that defendants could be released without charge after years in custody.
The military has been accused of arbitrarily arresting thousands of civilians during the conflict, which has left at least 20 000 and made over 2.6 million homeless since 2009.
Human rights groups claim most have been held in overcrowded, unsanitary conditions in military detention facilities, without access to lawyers or ever having appeared in court.
Since the violence began eight years ago, only 13 people have been put on trial and just nine have been convicted, according to government figures.
The lead judge and state prosecutors on Monday promised to be "just and fair" in the cases.