The BBC Correspondent Hilary Andersson in an exclusive interview with General Obasanjo

General Obasanjo was imprisoned by the late General Abacha in 1995 for allegedly plotting a coup and was released from jail last week.

When General Abdulsalam Abubakar took over as head of state following the unexpected death of General Sani Abacha two weeks ago, he released nine key political prisoners, including General Obasanjo, but not Chief Abiola.

On Thursday, he ordered the release of a further 17 detainees, but Abiola was still not among them.

Abiola - release may be imminent

Chief Abiola was the presumed winner of the 1993 elections that were annulled by the military, and since General Abacha's death, the international community and opposition groups have been calling for his release too.

General Obasanjo told our correspondent that he believed that Chief Abiola would be freed soon.

"Once this process had started, I believe it will continue," he said in an interview.

The BBC correspondent in Lagos says there is growing speculation that Abiola's release may be imminent.

'How can you reform the devil?'

Asked whether he thought that Abiola's release could be the start of the military trying to retain its credibility, General Obasanjo said that he thought there was still a long way to go.

General Obasanjo: "I absolutely believe Abiola will be released"

"After you have had two successive military governments that lied, deceived, oppressed, covered up, and did all sorts of things that this country had never known before, it would take more than just releasing one individual - or even all the political detainees - to really establish credibility and confidence," he said.

He also said that the moral standard in Nigeria had dropped, and that very few Nigerians still stand up for their principles.

He said that too many Nigerians tried to rationalise their support for Abacha because they believed they could influence him.

"Now who can tell you that he can reform the devil?" he asked.

"If it was possible for God to reform, he would have reformed Satan. And if God cannot reform Satan, then anyone who thinks he can reform an evil man is deceiving himself. He himself will become evil."