A Nigeria High Court has revoked bail for the leader of a separatist movement known as the Indigenous People of Biafra.

Justice Binta Nyako made the ruling Thursday, saying that Nnamdi Kanu had violated bail terms. She issued a warrant for his arrest.

Kanu, who faces five charges including treasonable felony, was granted bail in April 2017 on health grounds after spending 19 months in detention.

Nyako said the backers of Kanu's bail have withdrawn support because they do not know where he is. Kanu has been missing since September 2017 after his home was allegedly invaded by Nigerian army troops.

The separatist movement calls for the independence of Nigeria's former Eastern Region - which unsuccessfully fought for independence as Biafra in the 1967-1970 civil war.