Charles Ble Goude, the former right-hand man of Ivorian ex-president Laurent Gbagbo, has been moved from Abidjan to the holding cells of the International Criminal Court as it prepares to try him for crimes against humanity.
A court spokesman confirmed on Sunday that the 42-year-old former youth leader was put inside the court's detention centre, located inside a Dutch prison complex on the outskirts of Den Haag.
Ble Goude faces four counts of crimes against humanity, including murder and rape, allegedly committed during post-electoral violence in the west African country in 2010-2011.
He was on Saturday taken from Abidjan on a plane chartered by the ICC.
The former leader of the "Young Patriots", once known as Gbagbo's "Street General", was joining his former boss in ICC detention.
ICC prosecutor Fatou Bensouda said the court was a step closer to unvieiling the truth about the case.
The crisis in the country region started with Gbagbo's refusal to concede defeat in November 2010 elections, sparking armed clashes that killed more than 3,000 people.
His election rival, Alassane Ouattara, now the president, eventually removed him from power thanks to international military backing.
Gbagbo, who was transferred to The Netherlands in late 2011, also faces four counts of crimes against humanity but the court has yet to confirm the charges, pending further investigation.
Ble Goude galvanised support for Gbagbo during the crisis with fiery speeches urging mass mobilisation against what he called pro-Ouattara "rebels" and their foreign backers, former colonial power France and the UN.
Ble Goude "allegedly bears individual criminal responsibility, as indirect co-perpetrator, for four counts of crimes against humanity, namely murder, rape and other forms of sexual violence, persecution, and other inhuman acts," the ICC said Saturday.
The ICC issued a warrant for his arrest in December 2011 but did not make it public until late last year, and the Ivorian cabinet agreed to the transfer on Thursday.
The former youth leader for Gbagbo was arrested in Ghana in January 2013 after more than a year and a half on the run and extradited to Ivory Coast.
Ble Goude's lawyer on Saturday said Ivorian investigators had presented little evidence against his client.
"We are respectful of the law, but we are not afraid," he told the AFP news agency.
Ble Goude himself told AFP in a 2012 interview that he did not fear going to the ICC.
"I am not an advocate of weapons, I never maintained a single militia. If the ICC wants to invite me for having organised protest marches, I have no problem appearing before the ICC," he said.