Nigeria’s attorney general, Abubakar Malami, responded to Thursday's ruling in a statement saying the separatist is discharged but not acquitted.
Malami said authorities will explore legal steps to revisit the court's decision. He said the court failed to take into account issues that took place before Nnamdi Kanu was extradited to Nigeria from Kenya last year.
A three-judge panel of an appeals court Thursday ruled that Kanu’s trial was unlawful, and said authorities flouted international treaties to "abduct" the separatist.
The court said the circumstances surrounding his arrest did not give the government the jurisdiction to continue to keep him on trial.
The court also ruled that the government did not provide clear evidence of when and where Kanu committed the many allegations against him.
The attorney general's office did not immediately respond to calls for further comment. But Kanu's lawyer, Ifanyi Ejiofor, spoke to VOA via phone.
"The right of appeal is a constitutional right but the fact is that order of court must be obeyed, it's sacrosanct. Saying that Nnamdi Kanu was discharged not acquitted I believe is an impudence on the judgement of the court of appeals. The court used the word abduction, that is to tell you the level of the atrocity they committed," he said.
It's not clear when he will be freed.
"We expect them to comply immediately with the court order because detention became illegal as of yesterday. Yesterday, the court directed he should be released immediately. They should release him to us without any further ado," Ejiofor said.
Kanu is leading a movement to break off southeastern Nigeria from the rest of the country to form a republic called Biafra.
A previous Biafra independence movement led to a civil war between 1967 and 1970 that killed an estimated one million people.
On Friday, as news of Kanu's court discharge spread, so did excitement in Nigeria's Southwest region.
Christian Paul hails from Imo state, one of the strong bases for the separatist movement. He believes that with Kanu’s release, the court may have been sending a message.
"They violated his human rights and kept making fresh allegations against him. At this point in time, it becomes really strategic if his release is granted by a court. It might have some political undertone,” he said.
Nigerian voters head to the polls in February of next year to elect a new leader.
By Timothy Obiezu
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