A human rights lawyer is demanding the release of Nigeria's detained Shiite leader for medical treatment abroad to save his eyesight.

Ibraheem Zakzaky lost one eye in an army raid on his home and is in danger of losing sight in the remaining eye, according to an urgent appeal lodged with the High Court of Abuja by Femi Falana, a Shiite statement says Tuesday.

Zakzaky is detained without charge, even though Nigerian law requires that charges be brought within 48 hours.

Zakzaky's doctor has said he was shot seven times during a siege that ended three days of military attacks on Shiites in northern Zaria town in December. Hundreds of Shiites and one soldier were killed.

Nigeria's army claimed Shiites at an illegal roadblock wanted to assassinate the army chief.