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A notorious ex-warlord who became a general in the Congolese army despite international war crimes charges is now being blamed for fomenting more unrest in Congo's east and faces new charges of crimes against humanity.

As Bosco Ntaganda's loyalists started to split off from the military last month to form a new rebel group in the wilds of eastern Congo, he went into hiding and is accused of orchestrating the defection.

Human rights groups say Ntaganda had long been living openly in eastern Congo, dining at restaurants and playing tennis despite an International Criminal Court arrest warrant on allegations he forced children to serve as soldiers. Now the Congolese government has vowed to arrest him and the ICC announced Monday it is expanding the charges against him.

Ntaganda, though, is nowhere to be found. The ensuing violence from the defection of his supporters from the Congolese army has forced thousands to flee their homes.

"Ntaganda and his men are on the run," Congolese army spokesman Sylvain Ekenge said after authorities seized more than 20 tons of heavy weapons from a property Ntaganda owns.

The International Criminal Court believes all of this would have been avoided had Ntaganda been detained years ago. He was first indicted on war crimes charges in 2006, a warrant that was unsealed two years later.

"Bosco Ntaganda has used the time offered to him since the ICC arrest warrant was issued to move from Ituri to North Kivu, to expand his power on new territories, and to maintain a power base thanks to his crimes, and the violence of persons under his control," the ICC prosecutor said Monday.

"Now more than ever is the time to arrest him. His recent desertion from the (Congolese military) has shown once again that he cannot be trusted; it is a renewed demonstration that power through violence only leads to more violence," he said.

Bosco Ntaganda had been a commander of the National Congress for the Defense of the People, the rebel group known by its French acronym, CNDP, whose fighters launched a rebellion in late 2008. As part of a 2009 peace deal, the fighters were integrated into the Congolese army. Ntaganda was then allowed to wear the stripes of a general in the Congolese military, despite repeated appeals by the International Criminal Court.

Congo's president had refused calls to hand over Ntaganda, arguing his cooperation was essential to keeping the peace in the troubled east of the country where numerous local militias and foreign rebels operate.

Then in a marked turnaround last month, Congo's president called for Ntaganda's arrest though suggested Ntaganda may face trial before a Congolese court rather than abroad.Congo's military believes Ntaganda is currently orchestrating the defection by the former CNDP rebels, charges both the fighters and Ntaganda deny.

The mutinous soldiers have accused the government of failing to hold up its end of a March 23, 2009 peace accord, when the fighters agreed to be integrated into the Congolese army.

Following the April mutiny, the fighters fled into the bush, where they regrouped and later issued a press release on the letterhead of the former CNDP, saying that they had launched a new rebel group, called the M23 -- for March 23, in reference to the date of the 2009 peace treaty. Like the former CNDP, the M23 is dominated by fighters from the Tutsi ethnicity. Ntaganda is Tutsi and according to ICC arrest warrant he is believed to be Rwandan.

"Ntaganda is behind this new movement of mutinous soldiers, the M23, and the government can't negotiate with these people," said Congolese government spokesman Lambert Mende.

In a recent interview given to a local journalist in Swahili, however, Ntaganda maintained he "wasn't involved in this uprising in the east."

The governor of North Kivu province, though, has accused him "of being the instigator of everything happening in Kivu."

Pressure has been mounting for Ntaganda's arrest since the ICC recently convicted another Congolese warlord Thomas Lubanga of using child soldiers, the first judgment in the court's 10-year history.

On Monday, the court added additional counts to Ntaganda's indictment, accusing his forces of having "ethnically cleansed the areas by killing and raping civilians" back in 2002-2003. He already had been charged with using child soldiers for fighting in northeastern Congo from 2002 to 2003.

Ntaganda has vigorously denied all the allegations against him, and said in a 2010 interview with The Associated Press that he did not fear arrest on the ICC charges.

"I don't think that the U.N. is able to arrest me in Congo because they have arms that I also have and that can protect me when they try to arrest me," he said. "If it is established that I committed crimes, I won't hesitate to answer them to a court in my country. But I will never accept answering charges by the International Court."