African warlord Bosco Ntaganda was taken from the U.S. Embassy in Rwanda on Friday and put on a flight to The Hague, where he faces trial at the International Criminal Court on charges including murder, rape and persecution in a rebel group's deadly reign of terror that gripped eastern Congo a decade ago.

Ntaganda was due to arrive late Friday night, nearly seven years after he was first indicted. His transfer was hailed as a crucial step in bringing to justice one of Africa's most notorious warlords. It was also a welcome relief to a court that earlier this week dropped charges against a senior Kenyan suspect for lack of evidence and late last year acquitted another rebel leader accused of atrocities in Congo.

'Today those who have long suffered at the hands of Bosco Ntaganda can look forward to the future and the prospect of justice secured.'—Fatou Bensouda, ICC prosecutor

Nicknamed "The Terminator" because of his reputation for ruthlessness in battle, Ntaganda became a symbol of impunity in Africa, at times playing tennis in eastern Congo, apparently without fear of arrest.

U.S. Secretary of State John Kerry called the transfer "an important moment for all who believe in justice and accountability.

"For nearly seven years, Ntaganda was a fugitive from justice, evading accountability for alleged violations of international humanitarian law and mass atrocities against innocent civilians, including rape, murder, and the forced recruitment of thousands of Congolese children as soldiers," Kerry said in a statement. "Now there is hope that justice will be done."

M23 split creates weakness

Despite his 2006 ICC indictment, Ntaganda joined the Congolese army in 2009 as a general following a peace deal that paved the way for him and his men to be integrated into the military. He was allowed to live freely in the provincial capital of Goma, where he also dined at top restaurants.

Last year, however, the agreement between the former warlord and the Congolese government disintegrated, and he and his troops defected, becoming known as M23 and battling Congolese government troops in the country's mineral-rich east.

Ntaganda is believed to have turned himself in after becoming vulnerable when his M23 rebel group split into two camps last month over the decision to bow to international pressure and withdraw from Goma late last year. Ntaganda and another rebel leader, Jean-Marie Runiga, had opposed any pullout, but a rebel general, Sultani Makenga, ordered a retreat and initiated peace talks with the Congo government.

Rwanda's co-operation in the transfer of Ntaganda could come at a cost. If he testifies in The Hague, he could reveal details of Rwanda's alleged role in the conflict in Congo and support for M23.

A United Nation panel of experts last year said that both Rwanda and Uganda commanded and supported M23. Both countries deny the charge.

First voluntary surrender

Ntaganda was turned over to ICC staff in the Rwandan capital, Kigali, where he gave himself up at the U.S. Embassy on Monday. He is the first indicted suspect to voluntarily surrender to the court's custody.

The court's prosecutor, Fatou Bensouda, welcomed his transfer as a great day for victims in Congo.

"Today those who have long suffered at the hands of Bosco Ntaganda can look forward to the future and the prospect of justice secured," Bensouda said.

When he arrives in the Netherlands, Ntaganda will be taken to a cell in the court's detention unit to await his arraignment, scheduled for Tuesday, before a panel of judges. He will be given a medical checkup and appointed a defence attorney.

Rights groups welcomed Ntaganda's arrest.

"Ntaganda's expected trial will underscore the importance of the ICC in providing accountability for the world's worst crimes when national courts are unable or unwilling to deliver justice," said Geraldine Mattioli-Zeltner, international justice advocacy director at Human Rights Watch.

Child soldiers

Ntaganda was first indicted in 2006 on charges of recruiting and using child soldiers. In July last year, the court issued a second arrest warrant accusing Ntaganda of murder, rape, sexual slavery, persecution and pillaging in 2002-2003 in the eastern province of Ituri. He faces a maximum sentence of life imprisonment if convicted.

Prosecutors call Ntaganda the "chief of operations" of the Union of Congolese Patriots and its armed wing, the Patriotic Forces for the Liberation of Congo, known by their French acronyms UPC and FPLC. The groups waged a brutal military campaign to establish political and military domination for the Hema tribe over resource-rich Ituri, allegedly killing some 800 people in a few months.

According to court documents, his rebels used the same tactics in each village they attacked — surrounding the settlement and shelling it before going house-to-house to slaughter survivors with guns, machetes, spears and knives. The fighters allegedly raped women and abducted them to turn into sex slaves during the attacks.

Prosecutors say Ntaganda "planned and commanded scores of co-ordinated military attacks against the Lendu and other non-Hema tribes."

The former leader of the UPC/FPLC, Thomas Lubanga, last year became the first person convicted in the International Criminal Court's 10-year history. He was found guilty of recruiting and using child soldiers in fighting in Ituri and sentenced to 14 years imprisonment. He has appealed his conviction.

The alleged leader of a Lendu tribe militia in Ituri, Mathieu Ngudjolo, was acquitted in December of atrocities in Ituri.

While getting Ntaganda to The Hague is a significant step for the court, several of its highest-profile suspects remain at large, including Sudanese President Omar al-Bashir, who has been indicted for genocide in Darfur province, and Joseph Kony, leader of the shadowy Ugandan rebel movement the Lord's Resistance Army.

"As we welcome progress in one case, others also subject to ICC warrants in the region remain at large," Bensouda said. The international court has no police force and relies on co-operation of states to arrest and transfer suspects.