YENAGOA, Nigeria (Reuters) - The detained leader of a separatist group in Nigeria has filed a lawsuit alleging that he was illegally transferred from Kenya to Nigeria and demanding he be freed and allowed to go to Britain, according to media reports citing legal documents.
Nnamdi Kanu, who holds British citizenship, leads the Indigenous People of Biafra (IPOB) group which campaigns for part of southeastern Nigeria to secede and has been labelled a terrorist organisation by the Nigerian authorities.
Kanu spent two years in jail in Nigeria, but disappeared after he was freed on bail in April 2017. He was re-arrested in June this year and is being held in the capital Abuja where he faces trial for treason and other charges.
In a lawsuit against the Nigerian government and security services, filed in a court in southeastern Abia State, Kanu's lawyers alleged a series of violations of his fundamental rights, according to reports from several Nigerian media.
In particular, it said Kanu should be "repatriated" to Britain and that if Nigeria wanted to detain him it should make an extradition request to the British authorities.
The Abia court confirmed a suit had been filed and a hearing was scheduled for Sept. 21.
Reuters has asked the Foreign Office in London for comment.
Nigeria has not revealed the circumstances of Kanu's detention. Kenya has denied involvement.
Previously, Britain said it had offered Kanu consular assistance and asked Nigeria to explain the circumstances of his detention.
Kanu's detention has stirred tensions in the southeast, homeland of the Igbo ethnic group, a region that tried to secede in 1967 under the name Republic of Biafra, triggering a three-year civil war in which more than a million people died.
IPOB has repeatedly called on people across the southeast to stay at home in protest over Kanu's situation, and on some days markets, offices and schools have been deserted. The latest stay-at-home day is scheduled for Thursday, in protest at a planned visit to the region by President Muhammadu Buhari.
Amnesty International said in August that Nigerian security forces had killed at least 115 people and arbitrarily arrested or tortured scores of others as part of their crackdown on IPOB. Nigerian did not comment on the allegations.
(Reporting by Tife Owolabi and Angela Ukomadu, writing by Fikayo Owoeye, editing by Estelle Shirbon and Mark Heinrich)