Former president of Ivory Coast Laurent Gbagbo is to make his first appearance before the International Criminal Court at The Hague.
He faces four charges of crimes against humanity, including murder and rape, in the wake of Ivory Coast's disputed presidential elections a year ago.
Some 3,000 were killed in violence that followed Mr Gbagbo's refusal to accept defeat in the November 2010 polls.
Mr Gbagbo is the first former head of state to be brought before the ICC.
He is expected to hear the charges against him when he makes his first brief appearance in the court.
His transfer from Ivory Coast - where he had been under house arrest since April - to The Hague last week sparked anger from his supporters who described it as a "political kidnapping".
The 66-year-old is currently being held in an ICC detention centre.
'More to come'
Laurent Gbagbo's arrest follows an ICC investigation into the four months of conflict that began in Ivory Coast when he refused to hand power to his long-time rival Alassane Ouattara, who was declared winner of the election.
The charges relate to events between 16 December 2010 and 12 April 2011, the ICC said.
Mr Gbagbo is accused of being an "indirect co-perpetrator" in attacks that were "widespread and systematic... committed over an extended time period, over large geographic areas, and following a similar general pattern".
Louis Moreno-Ocampo, chief prosecutor at the ICC, says there is evidence of widespread and systematic attacks against civilians.
But troops loyal to Mr Ouattara are also suspected of carrying out abuses, and human rights groups have urged an investigation into crimes allegedly committed by other parties.
Mr Moreno-Ocampo said Mr Gbagbo is only the first to be brought to account and "there is more to come".
The ICC was set up in 2002 to prosecute and bring to justice those responsible for the worst crimes - genocide, crimes against humanity and war crimes - committed anywhere in the world.
It is currently hearing six other cases, all relating to crimes committed in Africa, including that of Jean-Pierre Bemba, former vice-president of DR Congo, whose trial began in November 2010.
It has issued an arrest warrant for Sudan's President Omar al-Bashir, who is accused of genocide and crimes against humanity.
Former Liberian President Charles Taylor is currently on trial in The Hague by the Special Court for Sierra Leone, set up jointly by the UN and Sierra Leonean government
Former Yugoslav President Slobodan Milosevic was on trial by the International Criminal Tribunal for the former Yugoslavia (ICTY) - an ad hoc UN court - at the time of his death in 2006.