Congolese war crimes suspect Bosco Ntaganda, dubbed "The Terminator", was en route from Rwanda to the International Criminal Court on Friday to face charges ranging from murder and rape to using child soldiers.
The first ever suspect to hand himself in to the ICC, he was wanted for war crimes and crimes against humanity allegedly committed during his years as a warlord in eastern Democratic Republic of Congo.
He shocked the world when he walked into the US embassy in Rwanda on Monday and asked to be sent to the Hague-based court.
Ntaganda was allegedly involved in the brutal murder of at least 800 people in villages in the volatile east of the DR Congo, using child soldiers in his rebel army and keeping women as sex slaves between September 2002 and September 2003.
He was in ICC custody aboard a plane from Kigali which was expected to arrive at Rotterdam airport late Friday night.
Dutch police will escort him to the ICC's detention unit in The Hague, a journey of around 25 kilometres (15 miles).
Ntaganda, born in 1973, will become the fifth African in the ICC's custody. He will face judges for the first time on Tuesday at 1000 GMT, after a medical checkup.
Judges will verify his identity and the language in which he will be able to follow the hearings and he will also be informed of the charges against him, the court said.
ICC prosecutor Fatou Bensouda welcomed news of Ntaganda's transfer, saying: "This is a good day for victims in the DRC and for international justice.
"Today those who are alleged to have long suffered at the hands of Bosco Ntaganda can look forward to the prospect of justice taking its course," she said in a statement.
US Secretary of State John Kerry hailed a major step for "justice and accountability."
"Now there is hope that justice will be done," he said in a statement.
Ntaganda's arrival in The Hague "will also send a strong message to all perpetrators of atrocities that they will be held accountable for their crimes," Kerry said.
Set up just over a decade ago, the ICC is the world's only permanent criminal court to try genocide, crimes against humanity and war crimes.
Geraldine Mattioli-Zeltner of Human Rights Watch said the arrival of Ntaganda at the ICC "will be a major victory for victims of atrocities in eastern Congo and the local activists who have worked at great risk for his arrest."
The expected trial will show the ICC's importance in "providing accountability for the world's worst crimes when national courts are unable or unwilling to deliver justice," she added.
Once a commander of the Democratic Republic of Congo's M23 rebels, Ntaganda is believed to have crossed into Rwanda at the weekend along with several hundred fighters loyal to him after they suffered a humiliating defeat at the hands of a rival rebel faction.
He will arrive in The Hague almost four years after the signing of a March 23, 2009, peace agreement with Kinshasa that integrated his earlier rebel group into the regular army and paved the way for him to become a Congolese general.
The failure of that deal sparked a mutiny by the rebels-turned-soldiers, who set up the M23.
The rebels have been fighting the Congolese army in the restive and mineral-rich North Kivu province since April.
DR Congo and the United Nations have both accused Rwanda of backing the M23, a claim Kigali has always denied.
Analysts said Ntaganda's transfer for trial would not have a major impact on peace efforts for eastern DR Congo.
"Bosco's arrest won't bring peace to the eastern Congo, but Bosco's arrest does spell a victory in the battle against impunity and the dismantling to one of the barriers to a peace process in the country," said Jason Stearns, author of several books on the region.