Nigeria's pro-Biafra leader Nnamdi Kanu is due to appear in court on Monday in the capital, Abuja, to face treason and other charges.

His group, the Indigenous People of Biafra, which is campaigning for an independent state in eastern Nigeria, is proscribed by the federal government.

Mr Kanu emerged as the new face of the campaign for an independent Biafran state, nearly half a century after more than one million people were killed in the separatist war.

He was arrested and extradited to Nigeria last month.