A UN-backed special court in The Hague is due to rule on an appeal by former Liberian President Charles Taylor.Last May, the court sentenced him to 50 years in prison for aiding and abetting rebels in neighbouring Sierra Leone during the 1991-2002 civil war.
He became the first former head of state convicted by an international war crimes court since World War II.
His lawyers want him acquitted arguing that legal and factual errors were made during the trial.
However, the prosecution has sought to increase his sentence to 80 years.
The BBC’s Chris Morris in The Hague says the court’s decision will be closely watched because the guilty verdict was hailed as a landmark, proving that even people at the highest level of power can be held to account.
Charles Taylor, 65, was found guilty of aiding and abetting war crimes in Sierra Leone, including terrorism, rape, murder and the use of child soldiers.
He was also found guilty of planning some of the attacks carried out by rebel groups in neighbouring Sierra Leone during the vicious civil war.
The former Liberian leader was arrested in 2006 and maintained his innocence throughout the trial.
If his appeal fails, Charles Taylor will serve his sentence in a foreign jail. The UK has offered to accept him at a British prison – alternative destinations include Sweden or Rwanda.
Our correspondent says it would take about a week to organise his transfer from The Hague.
BBC
