Sheikh Zakzaky has been held in custody for more than two years in Nigeria.
The top Shia cleric lost his left eyesight in a raid which was carried out by the Nigerian army on his residence in the northern town of Zaria in December 2015.
Zakzaky, his wife and a large number of the cleric’s followers have since been in custody.
Despite the ruling of a Federal High Court, which ordered his unconditional release in 2016, the Nigerian government has refused to set him free.
