Abuja (AFP) - The high-profile trial of a pro-Biafran leader opened in Nigeria's capital, Abuja, on Tuesday but was immediately adjourned pending defence applications against the charges.
Nnamdi Kanu, the head of the Indigenous People of Biafra (IPOB) movement, has been in custody since October 2015, sparking protests by his supporters across the country's southeast.
He and three others have been charged with treasonable felony, membership of an unlawful assembly, conspiracy to disturb public peace and terrorism-related offences.
A judge last month ordered that the identities of prosecution witnesses should be withheld because of fears for their safety.
Kanu, who also ran the London-based Radio Biafra station, opposes what he calls a "secret trial" and wants the case to be heard in public.
Members of the public were barred from the courtroom, reporters without official accreditation were not allowed in, while curtains blocked the view of the judge, defendants and lawyers.
Outside, IPOB members chanted "Freedom", waved placards and held aloft the Biafran flag -- a red, black and green horizontal tricolor with a golden rising sun.
Kanu's lawyer, Ifeanyi Ejiofor, told judge Binta Nyako an application had been filed challenging the court's jurisdiction to hear the case and the competency of the charges.
Ejiofor told reporters outside court there was "no merit" in the proof of evidence against the defendants and a prima facie case had not been made.
Nyako adjourned the case until Thursday to hear the submissions.
Separatist sentiment among the Igbo people, who are the majority in southeast Nigeria, has grown in the months since Kanu's arrest and sparked bloody clashes with the security forces.
The government has refused to release Kanu on bail, despite court rulings from at least three judges, including a regional tribunal.
Fifty years ago a unilateral declaration of an independent Republic of Biafra led to a brutal civil war that left hundreds of thousands dead, mainly from starvation and disease.
The conflict ended in 1970.