* Ntaganda was a leader of M23 rebellion in eastern Congo
* Accused of conscripting child soldiers, rape
* U.S. official says ready to send Ntaganda to ICC (Recasts with U.S. confirmation, Congolese spokesman, details)
By Jenny Clover
KIGALI, March 18 (Reuters) - Fugitive Congolese warlord Bosco Ntaganda surrendered at the U.S. Embassy in Kigali on Monday and asked to be transferred to the International Criminal Court to face war crimes charges, U.S. officials said.
Ntaganda's whereabouts had been unknown after hundreds of his fighters fled into Rwanda or surrendered to U.N. peacekeepers at the weekend following their defeat by a rival faction of M23 rebels in the mineral-rich eastern Congo.
U.S. officials said that Ntaganda, a veteran of more than 15 years of conflict in eastern Congo, simply had walked into the U.S. embassy in the Rwandan capital early on Monday.
"He specifically asked to be transferred to the ICC in the Hague," U.S. State Department spokeswoman Victoria Nuland told reporters in Washington.
"We are currently consulting with a number of governments, including the Rwandan government, in order to facilitate his request," she said.
Ntaganda faces charges of conscripting child soldiers, murder, ethnic persecution, sexual slavery and rape during an earlier conflict in the Ituri district of northeastern Democratic Republic of the Congo.
ICC spokesman Fadi El-Abdullah said the court would put in place all necessary measures to ensure a swift surrender.
A report by a U.N. panel of experts in October said Rwandan-born Ntaganda, nicknamed "The Terminator", was the leader of the M23 rebellion, which has pursued a year-long insurgency that embarrassed Kinshasa and U.N. peacekeepers by seizing the capital of North Kivu province, Goma, in November.
The experts said the rebellion was backed by Rwanda and Uganda, both of which allegedly sent troops to aid the insurgency in a deadly attack on U.N. peacekeepers. Both countries have repeatedly denied supporting M23.
TRAIL OF ATROCITIES
Congolese government spokesman Lambert Mende said Ntaganda had crossed into Rwanda on Saturday with help from the Rwandan army.
"We'd prefer to have him judged here, but if he is sent to The Hague, that's no problem either," Mende told Reuters. "The most important thing is that justice is served."
Ntaganda's apparent defeat at the hands of rival rebel commander Sultani Makenga on Saturday came after weeks of infighting within M23 ranks.
Neither Rwanda nor the United States has an obligation to hand over Ntaganda to The Hague-based ICC since they are not parties to the Rome Statute that established the court.
The M23 insurgency in resource-rich North Kivu was partly triggered by President Joseph Kabila's plan to arrest Ntaganda on the international charges. Ntaganda was integrated into the Congolese army alongside other insurgents as part of a 2009 peace deal.
The ICC has been seeking Ntaganda's arrest since 2006 but Kabila had resisted acting on the warrant until April last year, saying Ntaganda was a linchpin in the fragile peace.
"For over 10 years now, Ntaganda has left a trail of atrocities across eastern Congo, leading his troops to murder, rape, and pillage," said Ida Sawyer, researcher at Human Rights Watch.
"The U.S. now needs to make sure he faces justice for these alleged crimes by immediately sending him to the ICC in The Hague." (Additional reporting by Louis Charbonneau and Michelle Nichols in New York, Arshad Mohammed in Washington, Jonny Hogg in Kinshasa and Thomas Escritt in The Hague; Writing by Richard Lough)