The court's first-ever sentencing since it was established a decade ago comes after it unanimously convicted Lubanga in March for using child soldiers in his rebel army in 2002 and 2003, during the DRC's ethnic conflict.
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Fifty-one-year-old Lubanga, who founded the Union of Congolese Patriots and was commander of its military wing – the Patriotic Forces for the Liberation of Congo – denies abducting children and forcing them to commit atrocities in the DRC's north-eastern Ituri region, Al Jazeera reported.
He told the court that although he was being presented as a “warlord,” he “never accepted or tolerated such enlistments taking place."
During the trial, prosecutors told the ICC that while young boys were trained to fight during the DRC conflict, young girls were forced to work as sex slaves.
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Then chief prosecutor Luis Moreno-Ocampo pushed for Lubanga – who's been detained in The Hague since 2006 – to be sentenced to 30 years "in the name of each child recruited,” the BBC reported.
"These children were told to kill and rape. That was the education [Lubanga] gave these children," said Moreno-Ocampo, who has since been succeeded as ICC chief prosecutor by former Gambian justice minister Fatou Bensouda.
Human Rights Watch estimates that more than 60,000 people died in fighting between the Hema and Lendu ethnic groups in Ituri.
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